Get Ombudsmen to investigate and review Immigration NZ
The Ombudsmen Act 1975 makes it possible for an Ombudsman to make a finding and make recommendations about Immigration New Zealand's decisions.
Role and powers of the Ombudsmen
If your complaint with Immigration New Zealand has not been successful and you still believe that there are good grounds, then the next level up in the chain would be to lodge a complaint to the Ombudsman's Office.
You will need to have a good understanding of the immigration instruction (operation manual) and the relevant processes to be able to put together a good submission.
If you need to lodge a complaint to the Ombudsman's Office, it would be advisable to seek professional assistance.
New Zealand immigration law is constantly changing. Take action now and don't miss out.