The Government's Zero Carbon Bill passed with near-unanimous support on Thursday, after National agreed to support the climate change law. 

Despite supporting the bill National have set out several changes to the law that they would make in their first 100 days if elected, including removing the controversial methane target and asking an independent commission to set it.

National's votes are not needed for the bill to pass but are hugely important in setting out whether or not the law can survive across governments, a fervent hope of Climate Change Minister James Shaw.

Shaw met and negotiated with the party for close to a year on the bill, which passed by acclamation. 

The law will set up an independent climate change commission, which would advise governments on how to meet targets set in law by the bill – zero net carbon emissions by 2050 and a reduction of between 24 and 47 per cent of methane emissions by 2050. These targets are intended to keep global warming to within 1.5C by 2050.

A further methane reduction target of 10 per cent from 2017 levels by 2030 is also included.

Bridges told media that his party was not backing down to the Government.

These targets will be met with five-yearly "carbon budgets" recommended by the Commission.

Shaw hopes the bill will create a framework to reduce emissions over time much like the financial framework created in the early 1990s which has seen government debt greatly reduce.

National supported the bill through its first two readings but said further support was contingent on a series of changes that have not been made.

Bridges told media that his party was not backing down to the Government.

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"What is the responsible position for the National Party is to support the bill given that the framework the architecture of it we like, and make sure that we want changes to it," Bridges said.

"The framework is right. Certainty and stability around these things is right. And we would not change most of it - really just around the methane targets and food production."

PM: NZ WILL NOT BE A SLOW FOLLOWER

Prime Minister Jacinda Ardern pledged that her government would make sure New Zealand would not be in the middle of the pack on climate change, as National have advocated.

"New Zealand will not be a slow follower," Ardern said.

"We're here because our world is warming. Undeniably it is warming...We have to start moving beyond targets. We have to start moving beyond aspirations."

National's Judith Collins disagreed with the prime minister, saying "New Zealanders do not want to be first, fast, or furious. They want a fair go."

Shaw said on Thursday every side of the negotiations had to give up on something. He acknowledged Bridges and other National MPs for working constructively on the bill through "strong political pressures".

Methane makes up about half of New Zealand's emissions profile, with much of it coming from livestock belching. 

The farming lobby have strenuously fought efforts to reduce those emissions, and have generally found an ally in the National Party, who amended the last Labour government's Emissions Trading Scheme so agriculture would not be included.

National has faced pressure from its right to oppose the bill.

The right-wing think tank the New Zealand Initiative released a report on Wednesday arguing the bill could actually raise emissions by encouraging higher emissions offshore.

Federated Farmers' climate change spokesman Andrew Hoggard said late in October the Government had "missed a golden opportunity to take its farmers along with them" and the "unattainable goal will weigh heavy on some farmers".

Yet National relies on urban voters as much as it does rural ones, and Bridges has indicated a keenness to move the party into a more bipartisan space on climate change.

There was some talk of Collins crossing the floor to vote against the bill if her party ended up supporting it, but this has been quelled.

Collins tweeted on Thursday morning that "the flawed Zero Carbon Bill" would be supported by NZ First allied with the "anti-farmer Greens & Labour". She hinted that National would use the NZ First vote to challenge the party in the next election, saying she would see the party on the hustings.

The Government made a significant concession to the farming lobby in recent weeks with a delay on bringing agriculture into the Emissions Trading Scheme.

After that concession Shaw will be keen to deliver a strong Zero Carbon Bill for his Green Party base.

The Zero Carbon Bill was originally intended to be in force in April of 2019.

After months of delay its final two Parliamentary stages are happening in a single week.