It will be easier for the Police to seize illicit assets of criminals under a law change announced by the Government today.

Prime Minister Jacinda Ardern announced a "raft" of changes targeted at gangs at her post-Cabinet press conference on Monday, which were intended to strip gangs of the benefits of criminal activity.

The changes amend the Criminal Proceeds (Recovery) Act, expanding its measures to cover associates. This means that if someone is associated with an organised criminal group and it is suspected they could not have funded their assets legitimately, then they can now be required to prove to the court how they came to possess them – or face having them seized.

The threshold will be about $30,000 "unaccounted for", and the Government expects to seize about $25 million more due to the law change.

Ardern said there aren't many countries who have ventured into this space.

"This is the next frontier."

Ardern said there were tests in place to make sure the right people were being targeted, including listening to experts and police.

On the $30,000 threshold, Ardern said "there has been a range of views".

The Government is keeping an open mind and police would like to see it lower, she said.

Justice Minister Kiri Allan said the change was "about ensuring crime doesn't pay and that there are major consequences for criminal and gang activity".

• Police Association: Our gang problem isn't just a metropolitan one
• Christopher Luxon: Our objective here is to dismantle and disrupt gangs
• Police Association: Would be naïve to think Hipkins can solve crime overnight

She said that under the current regime, "organised criminals structure their affairs to avoid their illicit assets being restrained and forfeited".

"This is done by creating distance between themselves and the assets by putting property into associates' names," she said.

Allan's message to people hiding assets is "time is up".

When asked about why the Government was focusing on seizures just now, Allan said they've been working on it for some time.

It's technical and has required a lot of engagement, she said.

Allan said "a number of cases" have come up through the courts showing some criminals are using KiwiSaver to stow away misbegotten gains.

She didn't know specifically how many cases there have been, but believed it was a "significant number".

Police Minister Chris Hipkins said the problem was widespread.

"Police's experience with criminal proceeds investigations tells us that use of intermediaries, third parties, relatives or friends are a feature of many cases now investigated," Hipkins said.

"The steps taken today continue the Government's multi-faceted approach to tackling the harm caused by gangs and other organised criminal groups.

"This is the next step in the Government's work to curb crime and make our communities safer. It will mean that not only do we have more frontline Police than ever before, they also have greater powers to hit gangs where it hurts," he said.

The law change will grant police new powers to target the associates of organised criminal groups and restrain their property, when it is clear their legitimate finances would've been unlikely to have enabled them to acquire the assets.

It will also create a new court order that will mean criminals based overseas who have assets in New Zealand will face losing those assets, unless they can provide proof within two months that they obtained their property legally.

The law change will also allow the Government to seize the funds in KiwiSaver funds, eliminating the potential for criminals to hide illegal funds in their KiwiSaver.

The Government was concerned criminal groups had been structuring their activities to make it appear that property acquired through the proceeds of crime was not linked to them, but was owned via an associate.

Criminals could register things like property and vehicles to the names of associates and family members to avoid linking them to criminal activity.

National has already come out against the changes.

Responding to reports the bill was set to be introduced, the party's police spokesman Mark Mitchell told Newstalk ZB that while he supported seizing gang assets, the bill missed the bigger issue.

"They are not going to make any tangible impact right now on the amount of gang violence and gun violence that we're currently experiencing," Mitchell said.

The Act Party called the bill a "U-turn".

The party's justice spokeswoman Nicole McKee said Labour had "finally accepted the logic Act has been promoting for years, if you want to tackle the gangs you need to hit them where they hurt – their wallets".

"If you take the profit out of gangs then you take away the incentive. If there's money to be made they'll find a way around law enforcement. If there's no money to be made they'll give up," McKee said.