Have a look here:
https://www.ird.govt.nz/internationa...ency/personal/
If you are a New Zealand tax resident you are taxed on your "worldwide income" - that is income from New Zealand as well as from other countries. If you receive overseas income while you're a tax resident of New Zealand, you'll need to declare it to us on an Individual tax return (IR3).
https://www.ird.govt.nz/income-tax-i...g-your-return/
At the end of each tax year (31 March) some taxpayers need to confirm the amount of personal income tax to be paid. This is done by filing an Individual income tax return (IR3).
You need to file an IR3 return if you earned income other than salary, wages, interest, dividends, and/or taxable Māori authority distributions.
So assuming you are a NZ tax resident (which is defined on the first link) you will need to file a tax return and pay taxes on your income. All the info is on the IRD site, and you can phone them if you have questions.