Interest or dividend income you earn is usually taxed as you earn it. If you pay too much or too little tax this can be tidied up at the end of the tax year. You'll need to include this income and the tax you've already paid on an Individual income tax return (IR3).
At the end of the financial year, your bank will issue you a resident withholding tax summary. This is usually sent out in May by most banks, but if you don't receive a statement you may need to contact your bank to request one. These can also be downloaded easily from some banks such as ANZ, BNZ, Westpac and ASB.
If you still have any questions please let your accountant know. Alternatively you can also call us on 0800 555 024 or email firstname.lastname@example.org.