National is calling on the Government's spending watchdog to investigate what leader Judith Collins is calling a taxpayer-funded emboldening of gangs.

Newstalk ZB can reveal National has written to the Auditor-General, asking the office to investigate "significant concerns" with, what it says is, taxpayer money going to the Mongrel Mob.

"It has become clear that the Government does not see the seriousness of New Zealand's gang problem," Collins said.

"This is a very bad decision from a Government which would rather cosy up to gangs than keep New Zealanders safe."

Collins cited two recent incidents which she said prove this point.

The first is a $200 cash koha donation from Human Rights Commissioner Paul Hunt to the Mongrel Mob after he spoke at a recent hui.

The second is spending $2.75 million on an East Coast-based meth rehabilitation programme, with gang connections.

Collins, and her Police spokesman Simeon Brown, have written separate letters on both issues asking for the Auditor-General, John Ryan, to investigate these issues.

It is Ryan's job to make sure all Government spending is above board and appropriate; he can investigate areas which he feels need looking into.

Ryan will advise at some point in the coming weeks if he thinks these issues warrant further examination from his office.

But Collins and Brown feel strongly these matters need to be looked into.

Earlier this month, it was revealed a Government-funded a meth rehabilitation programme with Mongrel Mob connections.

The $2.75m Kahukura scheme was paid for through the Proceeds of Crime Fund – a pot of money confiscated from criminals used to pay for crime prevention programmes.

The programme – which is a live-in marae-based programme using a mix of Te Ao Māori and western methodologies – aims to address past trauma and drug use, instil better coping mechanisms, and prevent relapse.

That programme is run by the Hard to Reach organisation; co-run by Mob associated Harry Tam.

Justice Minister Andrew Little has said Tam is a "former" gang member.

But Collins questions this claim – citing a video from November last year where he's wearing a Mongrel Mob gang patch while giving a speech – as evidence Tam is more gang-connected than Little suggests.

Prime Minister Jacinda Ardern was one of the ministers to sign off this project, saying it has had proven results.

"It's a marae-based programme that yes, the participants ... are gang-affiliated participants, who have been involved in meth-related crime and activity, who have this meth addiction," she told RNZ.