Accountants provide a full range of personal and business accounting services is available to individuals, property investors and businesses. You will make your life a whole lot simpler if you keep accurate, tidy, and up to date accounting records. The best way to do this is to make sure you set up a separate bank account for your investment/rental property. Get monthly bank statements and enter them into a simple spreadsheet or accounting package. Accounting packages are relatively cheap and well worth the investment. Accounts Online has an entry level option for a few hundred dollars. Also spend 10 minutes with your accountant to make sure you give them the information the way they want it, this will help keep your accounting fees down.
Make sure you keep all your invoices relating to expenditure so you can provide proof to the IRD should they want to check. You will need to keep these for seven years. To obtain the IRD record keeping checklist click here