SWITCHING TAX RULES ON YOUR RENTAL PROPERTY

Switching tax rules on your rental property. What does that actually mean? Inland Revenue issued interpretation statement IS 25/08(opens in new tab) on 4 April 2025, and it tackles a problem that trips up more property owners every year: what happens, tax-wise, when your property’s use changes and it moves between the standard tax rules and the mixed-use asset rules. If you’ve ever turned a bach(opens in new tab) into a permanent rental, moved out of a flatting property, or started renting a room on Airbnb after years of long-term tenancy, this statement speaks directly to you.

30-Second Summary

• Every income year, you need to work out afresh which rules apply to your residential property: the standard tax rules or the mixed-use asset rules. Last year’s answer doesn’t carry over automatically.
• The mixed-use asset rules apply when you partly use a property to earn income, partly use it privately, and leave it unused for at least 62 days in the year.
• If your property doesn’t meet that test, you fall back to the standard tax rules — and then you need to check whether the residential property ring-fencing rules limit your deductions.
• Quarantined expenditure (from the mixed-use asset rules) only offsets against income in a year when the property is a mixed-use asset again. It doesn’t disappear if the rules change — it just sits there, carried forward.
• Unused excess deductions (from the ring-fencing rules) work the same way: they only offset against residential income in a year when the ring-fencing rules apply again.
• Ring-fencing or the mixed-use asset rules can suspend depreciation deductions too, but suspending or limiting a deduction never changes how you calculate the depreciation loss going forward — the adjusted tax value carries on as if you’d claimed the full amount.
• When you sell a depreciable item (fridge, carpet, furniture), whether you can use those carried-forward amounts against any recovery income depends entirely on which rules apply in the year of sale.

Use the chart above as your annual checklist, then read on for the detail — because the devil, as always, is in the timing.

Why This Distinction Actually Matters

New Zealand’s tax law treats residential property income very differently depending on how you use the property. Get the classification wrong, and you either overclaim deductions (Inland Revenue will eventually claw these back and add penalties and interest) or underclaim them (which just means you pay more tax than you need to).

The two regimes that matter here are the mixed-use asset rules and the standard tax rules. Most property owners assume their situation is straightforward: rent it out long-term, apply the standard rules, done. But life doesn’t always cooperate. You buy a holiday home and let it out between family visits. Or you flat in your own rental while advertising a spare room on Airbnb. Perhaps you move overseas for eighteen months and rent out your main home, then move back in. Each of these scenarios can shift which set of rules applies — sometimes within the same income year, sometimes from one year to the next.

IS 25/08 doesn’t introduce new law. It pulls together how the existing provisions interact when a property crosses from one regime into the other, and it earns its keep because the interactions aren’t intuitive. Anyone who mechanically applies last year’s approach to this year’s return can easily miss income, overclaim losses, or lose the chance to use expenditure the law still lets them carry forward.

The Two Sets of Rules, in Plain English

Mixed-use asset rules

A residential property becomes a “mixed-use asset” for an income year if, during that year, you:

• partly use it to earn income,
• partly use it privately (this includes use by people associated with you, or tenants who pay less than 80% of market rent — so-called “mates’ rates”), and
• leave it unused for at least 62 days.

If your property ticks all three boxes, you must apportion your expenses using a formula: multiply the expenditure by income-earning days, then divide by the sum of income-earning days and other counted days of use. The idea is simple even though the formula looks fiddly — the proportion of your costs you can deduct should reflect how much the property actually earned you income relative to how much you used it yourself.

There’s an important carve-out: if the property’s only income-earning use in the year was as a long-term rental, the mixed-use asset rules don’t apply at all, even if the property sat empty for stretches beforehand or afterward. Long-term renting on its own routes you straight to the standard tax rules.

If your mixed-use asset makes a loss and your income from it comes in under 2% of the asset’s value, the quarantined expenditure rules kick in. You can only deduct expenses up to the amount of income you actually received from the asset. Anything beyond that doesn’t vanish — you quarantine it and carry it forward to offset against future income from the same asset.

Standard tax rules

If your property isn’t a mixed-use asset for the year, you fall back to the standard tax rules. Under these, you deduct expenses that relate solely to your rental activity in full, and apportion anything that serves both private and income-earning purposes.

Once you’re under the standard tax rules, you then need to check whether the residential property ring-fencing rules apply. These rules stop you from offsetting a loss on your rental property against other income, such as salary or wages. If your deductible expenditure exceeds the income the property generates, you don’t lose the excess — it becomes an unused excess deduction, and you carry it forward to offset against future residential income.

There are exclusions from ring-fencing worth knowing. The main home exclusion applies if more than 50% of the land is your main home and you use it as your main home for more than 50% of the income year. The mixed-use asset exclusion applies automatically whenever the property is a mixed-use asset for that year — the two regimes are mutually exclusive within a single income year, which is exactly why the switching rules matter so much.

How to Work Out Which Rules Apply, Every Single Year

This is the part people get wrong most often: you have to reassess which rules apply every income year, not just when you first buy or change the use of a property. The mixed-use asset rules and the ring-fencing rules both operate on an income-year basis, so a property that was standard-rules last year could be a mixed-use asset this year, and vice versa.

Run through this each year:

1. Was the property’s only income-earning use as a long-term rental? If yes, standard tax rules apply — skip the mixed-use asset test entirely.
2. If not, did you use the property privately during the year (including use by associated persons, or at below-market “mates’ rates”)? If no, standard tax rules apply.
3. Did the property sit unused for at least 62 days during the year? If no, standard tax rules apply.
4. If you answered yes to both private use and the 62-day threshold, the mixed-use asset rules apply for that year.

Once you know which regime governs the year, you then layer on the relevant sub-rules — apportionment and quarantining for mixed-use assets, or ring-fencing (and its exclusions) for standard rules.

Keep good records. Inland Revenue expects you to be able to demonstrate, at the end of each year, which category your property fell into and why — bookings calendars, tenancy agreements, and a simple log of who stayed when will save you a lot of grief at tax time.

What Happens to Carried-Forward Amounts When the Rules Change

This is where IS 25/08 earns its keep, because the interaction between prior-year carried-forward amounts and a change in rules is genuinely counterintuitive.

Quarantined expenditure

If you’ve got quarantined expenditure sitting from a year when your property was a mixed-use asset, you can only use it against asset income — taxable income you derive from using the mixed-use asset — in a current year. If your property has since become a standard, long-term rental and is no longer a mixed-use asset, you derive no asset income, full stop. That means you cannot use the quarantined expenditure this year, even though you might have plenty of rental income coming in under the standard rules.

The quarantined expenditure doesn’t disappear. It keeps carrying forward, patiently waiting for a year when the property becomes a mixed-use asset again and you derive asset income from it. If you sell the mixed-use asset while quarantined expenditure remains unused, though, you generally forfeit it — a narrow exception applies for a replacement asset that’s identical or substantially the same as one you lost or damaged, but otherwise the expenditure dies with the sale.

Unused excess deductions

The mirror image applies to unused excess deductions from the ring-fencing rules. You can only offset these against residential income in a year when the ring-fencing rules actually apply to the property. If the property becomes a mixed-use asset (which triggers the ring-fencing exclusion) or qualifies for the main home exclusion, the ring-fencing rules step aside for that year — and so does your ability to use the carried-forward excess deductions against that property’s income.

Again, nothing is permanently lost. The unused excess deductions simply keep carrying forward until a year when the ring-fencing rules are back in play.

If you run a portfolio of properties under the ring-fencing rules (the default position, unless you’ve elected property-by-property treatment), there’s an added wrinkle. A property that’s ever been part of your portfolio stays part of it, even in a year when an exclusion applies to it. But in that excluded year, neither its income nor its deductions count toward the portfolio calculation — so you can’t offset other properties’ deductions against the excluded property’s income, and you can’t use portfolio-level unused excess deductions against it either.

Depreciation Gets Complicated Too

Chattels you use in a residential property — stoves, carpets, furniture, fridges — can still attract depreciation deductions, even though the building itself hasn’t been depreciable since the 2011–12 income year. Working out how much of that depreciation loss you can actually claim depends on which rules apply in the year, and switching between regimes doesn’t change the underlying maths.

Under the standard tax rules, if you use the chattel wholly to earn income, you claim the full depreciation loss (subject to any ring-fencing suspension). If you only partly use it to earn income, you apportion the claim using a formula based on qualifying use days over all days.

Under the mixed-use asset rules, you apportion the deduction using the same expenditure formula that applies to your other costs, and the quarantined expenditure rules can further limit it.

Here’s the crucial point: whatever proportion of the depreciation loss you couldn’t claim in a given year — because ring-fencing suspended it or the mixed-use asset rules quarantined it — doesn’t change how you calculate the depreciation loss in the following year. The adjusted tax value rolls forward as if you’d claimed the full deduction. You just track the suspended or quarantined amount separately, because it matters enormously later, when you eventually sell the item.

Selling Depreciable Property After a Rule Change

When you sell a depreciable chattel, you need to work out depreciation recovery income (if you sell for more than its adjusted tax value) or a depreciation loss on sale (if you sell for less). The calculation method itself is identical whether the standard tax rules or the mixed-use asset rules apply in the year of sale — the formulas in the Income Tax Act 2007 don’t care which regime you’re under.

What does depend on the current year’s regime is what you can offset against that recovery income:

• You can offset unused excess deductions carried forward under ring-fencing against depreciation recovery income, but only if the ring-fencing apportionment mechanism actually applies to the property in the year you sell the item. If the property is a mixed-use asset in the year of sale, ring-fencing doesn’t apply, and those carried-forward deductions sit on the sidelines.
• Mixed-use asset quarantined expenditure, on the other hand, can never offset depreciation recovery income, regardless of which rules apply in the year of sale. That’s because depreciation recovery income isn’t “asset income” — it arises from the disposal of the item, not from its use — and the quarantining provision only ever lets you offset against asset income.

This matters in practice. If your rental property has been sitting under the standard rules with a pile of unused excess deductions, and then it briefly becomes a mixed-use asset in the very year you happen to sell a big-ticket item like a heat pump or a new kitchen suite, you could end up paying tax on the recovery income with no carried-forward amounts available to soften it.

A Worked Example, Simplified

Consider a straightforward version of the kind of scenario IS 25/08 walks through. Say you own a bach that you use privately for part of the year, rent out as short-stay accommodation for another part, and leave vacant for more than 62 days. That’s a mixed-use asset. You make a loss, and because your rental income comes in under 2% of the property’s value, the quarantined expenditure rules trap some of your expenditure.

The following year, you decide you’re done with short-stay guests and let the bach to long-term tenants instead, moving out entirely. The property no longer meets the mixed-use asset criteria — it’s now under the standard tax rules — and, because you’re no longer living there, the main home exclusion doesn’t help you either. Ring-fencing applies.

In this new year, you cannot touch the quarantined expenditure from the mixed-use asset year, because you’re not deriving any asset income anymore. It just carries forward, waiting. Meanwhile, any loss this year becomes an unused excess deduction under ring-fencing, ready to offset against future residential income from the same property (or portfolio).

If, a few years down the track, you turn the bach back into short-stay accommodation and it becomes a mixed-use asset again, the original quarantined expenditure finally has somewhere to go — offset against the asset income you derive that year. Ring-fencing, though, would then lock the unused excess deductions from the standard-rules years back out again, because it no longer applies while the property is a mixed-use asset.

This back-and-forth is exactly why annual reassessment matters, and why you need to keep careful records of what you carry forward and why.

Key Takeaways to Remember

• Reassess which rules apply to each residential property every income year — don’t assume continuity from last year.
• Mixed-use asset status requires all three conditions: income-earning use, private use, and at least 62 unused days.
• Long-term rental as the sole income-earning use always routes you to the standard tax rules, regardless of vacancy periods.
• Quarantined expenditure only offsets against asset income in a mixed-use asset year; unused excess deductions only offset against residential income in a ring-fencing year.
• Depreciation losses keep accruing normally on the adjusted tax value even when ring-fencing suspends or the mixed-use asset rules quarantine a deduction — track the suspended amounts separately.
• Unused excess deductions can offset depreciation recovery income on sale (if ring-fencing applies in the sale year), but mixed-use asset quarantined expenditure never can.
• Keep a clear annual record — bookings, tenancy dates, days of private use — because the classification decision rests entirely on the facts of that specific income year.

Summary

Switching tax rules on your rental property can be confusing. IS 25/08 doesn’t change these underlying rules. Rather, it clarifies how those rules interact when a property shifts between regimes. The core message is consistency of process, not consistency of outcome. Work through the same classification questions every year. Keep meticulous records of use. Track any quarantined expenditure or unused excess deductions carefully. They can sit dormant for years before you can use them again. Miss a year’s reassessment, and you risk overclaiming deductions you’re not entitled to. You also risk missing out on offsets you’ve legitimately earned.

Get It Right Every Year

Property owners routinely misunderstand the rules around mixed-use assets and ring-fencing. These are two of the trickiest corners of New Zealand tax law. Getting the classification wrong can carry significant penalties.

Has your rental property’s use changed? Maybe you’ve moved overseas, or shifted from Airbnb to long-term tenancy. Maybe your family bach now sees more or less private use than before. Either way, get in touch with the team at Epsomtax.com. We specialise in residential property tax. We can help you work through the mixed-use asset rules and the ring-fencing rules, and everything in between. That way, you claim exactly what you’re entitled to — and nothing you’re not.