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

The Opposition party is asking the Auditor-General to look into $2.75 million paid to a Mongrel Mob-led methamphetamine addiction programme.

The money came from the Proceeds of Crime Fund which was signed off by Labour Cabinet Ministers, including Prime Minister Jacinda Ardern.

Political commentator Peter Dunne told Mike Yardley the Auditor-General could initiate a probe, but it would be an unusual thing to do.

"These are intensely political areas, and the auditor general's role is not to make a judgement on politics, but to make a judgement on the validity and the legality of expenditures."

Dunne adds it is unlikely the auditor general will get in involved, and there must be an agreement of sorts between the provider and the Government over this.

"What the auditor general would want to look at if he was to take it on would be the extent to which the conditions of that have been met or breached."