The IRD gives you a fairly good guide here under the heading "Deductions You Can and Can't Claim." You might also find this info helpful:
What info should you keep for your rental property? Your accountant should be able to give you a specific list based on your situation, but here is a general guide.
This list assumes you are using a property manager. All costs are for the 12 months preceding 31 March:
In our view, Home Office expenses can be claimed if you have rental property; however, as it is generally passive income (unless you are managing the properties yourself) we recommend a conservative claim, as follows:
For the rental property:
If you'd like a downloadable copy, please see below.
Why keep good records? The better your records, the more expenses can be legitimately claimed, and the better the tax result is for you.
Other FAQs you might have:
USING ACCOUNTANCYONLINE.CO.NZ/MY TAX QUESTIONNAIRE
HOW DO I DOWNLOAD TRANSACTIONS FROM MY BANK'S ONLINE INTERNET BANKING?
WHAT IS XERO.COM?
WHAT'S THE PROCESS FOR MY TAX RETURNS?
Accounting for your rental residential investment property; general taxation advice.