The ACT Party has revived its 2023 election policy to disestablish the Climate Change Commission.

Candidate Paul Henry says if elected, the party would transfer the commission's monitoring and reporting duties to existing bodies.

But the move was not just about cutting duplication and cost, he said.

"Their barking mad recommendation to increase our 2050 emissions reduction commitment would have lowered GDP by 2.2 percent.

"That's around $2 billion a year by 2035, rising to about $12.5 billion every year by 2050, wiped from our economy to meet an arbitrary target."

The commission had put forward proposals "even Labour and the Greens can't get behind", Henry said, pointing to the Labour-led government rejecting a recommendation to tighten Emissions Trading Scheme restrictions.

"Even the left could recognise a stupid idea."

Henry said the Ministry for Cities, Environment, Regions and Transport (MCERT) already measured greenhouse gas inventory and managed the Emissions Trading Scheme.

"Having the Climate Change Commission on top of that creates unnecessary duplication and costs on taxpayers that must be eliminated," he said.

ACT would instead make MCERT responsible for assessing the country's progress towards emissions targets.

In 2023, ACT leader David Seymour said its climate policy was " the best any political party has put forward".