More than $435 million worth of property, cars, cash and other assets has been frozen in New Zealand under a contentious law used to target gangs.

The Criminal Proceeds (Recovery) Act 2009 allows police to freeze and take someone's assets without ever finding them guilty of any criminal activity or even laying criminal charges.

The Government said the law gave police greater abilities to stifle gang activity, but lawyers said the move was an overreach and brought fundamental civil liberties into question.

Assets worth $435.6 million have been seized under the Act since 2009. More assets were seized last financial year than any other, with assets worth $115.9m frozen by police - $39.3m more than any other year.


So far, $66.6m worth of assets have been sold by the state, with $36.8m going into the Proceeds of Crime fund for law enforcement and education initiatives.

Assets which police suspected had been acquired as a result criminal activity could be restrained and forfeited to the Crown on the civil standard of proof, "the balance of probabilities" - a lower level than the criminal standard of "beyond reasonable doubt".

Police Minister Judith Collins said the act had been working effectively.

"Police have been extremely successful in investigating and seizing the dirty money of criminals and gangs since the Government passed this legislation.

"Police use all of the tools at their disposal, including the legislation which has strengthened their ability to go after the assets and profits of organised criminals."

She said 88 per cent of restraints and 96 per cent of forfeitures have been linked to drugs and/or organised crime.

She said the outcome of cases was determined in court.

Last month, senior Mongrel Mob member Valentine Nicholas had $1.17 million worth of his assets forfeited to the Crown, despite being not guilty of the criminal charges laid against him.

Lawyers said the overall intent of the law was positive but aspects of its application should be questioned.

The removal of a criminal conviction necessary for asset forfeiture was a significant change from the old legislation, the Proceeds of Crime Act 1991, said lawyer Graeme Edgeler.

Mr Edgeler said it was not fair for the Crown to take someone's house, cars and savings without proving criminal activity.

"The Government should not have the power to punish you unless it can prove to a pretty high standard that you've actually done something illegal," Mr Edgeler said.

"Even if there's a 49 per cent chance you're completely innocent, that the Government can take away everything you've worked for is pretty serious."

Labour police spokesman and MP Stuart Nash said he supported the law, but only if the offending was proven in court to a criminal standard.

"If you gain wealth or assets out the proceeds of crime, you should hand them back to the state when you get caught.

"I would be very uncomfortable with seizing citizens' assets without proof of guilt. Reasonable probability is not strong enough."

He said he was concerned about what seemed to be targeted action toward gang activity rather than other forms of organised crime.

"I suspect [it is] because targeting gangs make good headlines, and every government likes to be seen to be tough on gangs, whereas white collar crime [is] not as newsworthy," he said.