Currently, children adopted overseas via the ICANZ programmes gain NZ citizenship or PR. Some gain citizenship by grant, some by descent. If you or your child have gained New Zealand Citizenship by Descent, you need to know that NZ Citizens by Descent have all the rights of New Zealand citizenship, except that they cannot pass on their citizenship to any children born to them (or adopted) overseas.
This can create problems if you (the adopted person) go to live in Australia or elsewhere.
The adopted person needs to apply for Citizenship by Grant, while living in New Zealand. Normally anyone applying for Citizenship by Grant must have resided in NZ for at least five years, but for children, if the adoptive parents have lived in New Zealand for more than five years, you can apply for your child's NZ Citizenship by Grant well before 5 years, even immediately after you return to NZ with your child in some cases. The application can be done by the adoptive parent, or by the adopted person themself once they are 16. See information on changing your status from Citizenship by Descent to Citizenship by Grant on the Dept of Internal Affairs website.
You can download the form for applying for Citizenship by Grant at the New Zealand Department of Internal Affairs website.
We recommend that you indicate on the form or in a letter that it is a "descent to grant" application and send the completed application by courier to the Wellington office, not your local DIA office, with a prepaid return courier bag.
Processes, costs, requirements and DIA staff do change, so if in doubt call the Wellington Citizenship office and ask to speak to someone about changing from Citizenship by Descent to Citizenship by Grant. Your adoption documents are vital, often irreplaceable documents - enclose a self addressed return courier envelope and record the tracking number of both your courier envelopes. Make photocopies of everything before you send them away and enclose a list to make it clear what you have sent. Keep originals in a VERY safe place.