Maori Party MP Hone Harawira says his claims that the police have illegally taken DNA samples from teenagers may end up at the Independent Police Conduct Authority (IPCA).
The MP says he knows of six or seven teenagers who have been unfairly pressured by the police to provide samples.
The Police Minister and Commissioner of Police say if that has happened, a formal complaint should be made.
Mr Harawira says teenagers have been asked to give a sample so they can be identified if they go missing or die, or because their relatives are likely to be criminals.
Mr Harawira says he is talking to the teenagers' families about whether they would be prepared to take their cases further, and it will be their decision.
The MP is standing by his description of the police using Nazi-style tactics to collect the DNA samples.
Lawyer knows of case
A criminal lawyer says he knows of at least one case in which police officers coerced a teenager into giving a DNA sample.
Lawyer Graeme Newell told Nine to Noon he was rung in 2006 by a teenager who was offered cigarettes in return for a sample, while he was being held at a police station.
He says the police are ambitious when it comes to collecting as many DNA samples as possible.
Police say that they and the forensic science service have systems in place to identify samples taken in error from those under 17, which are then destroyed.
Complain, says Commissioner
Police Commissioner Howard Broad says officers operate within strict guidelines and if Mr Harawira is worried about how police are collecting DNA he should raise it with them directly, and lay a formal complaint.
Police say instructions make it clear samples must be given willingly, and that they're rendered invalid if any inducements have been made.
At present, police can only take voluntary samples from those under 17 to compare directly with DNA found at a crime scene.
From July, those aged between 14 and 17 can be required to give a sample, but under strict conditions, including having a parent or guardian present, and when charges for specified offences are imminent.
Minister challenges Nazi comparison
Police Minister Judith Collins says she is sorry that any comment has been made about so-called Nazi-style behaviour because that is not the way of the New Zealand police.
She says that if Mr Harawira knows of any case where DNA samples have been collected unlawfully, he should raise it with police or the Independent Police Conduct Authority.
The minister says she will not be asking the police to investigate the claims, and anyone with a case can go to the IPCA.
However, the senior solicitor at the nationwide Youth Law service, John Hancock, says many young people would not know the IPCA existed or think to seek legal advice.
Labour Party leader Phil Goff says Mr Harawira has insulted police by comparing them with Nazis.
Mr Goff says the comments are over the top.