Resident Withholding Tax (RWT) is a tax deducted on interest earned from investments and bank accounts. The investment organisation or bank deducts this tax when they credit interest to you.
Companies may also deduct withholding tax from dividends paid to shareholders.
If you receive interest as income you need to:
Provide the interest payer with your IRD number, and
Elect the tax rate at which this is to be deducted by them
The RWT tax rate used will vary for individuals and different types of business entity.
For more information on RWT, the tax rate and how this tax applies to interest and dividends refer to the IRD website