Kia Ora,
Depend on the structure of your business. If it’s for companies-under the new rules from 1 April 2020, if you have not provided your IRD number to your bank, tax will be deducted from your interest payments at 45%.
If you’ve provided your IRD number and company status to the bank, you may use either the 28% or 33% rate (Most companies-28% or Trusts and trustees – any income the trust earns-33%). If you do not choose a resident withholding tax rate, tax will be deducted from your interest payments at 28%.
If the resident withholding tax rate you choose does not match your income tax rate you may receive an end of year tax bill. If you do not choose a resident withholding tax rate, tax will be deducted from your interest payments at 33%.
For information on your business income tax obligations, best to talk to your accountant or tax advisor. Hope this helps. Wish you all the best.