A coalition bitterly divided over climate policy may need to find a hasty resolution as MPs tussle internally over whether to back Labor's emissions reduction target.
A Liberal heavyweight has threatened to abandon his post if the coalition remains committed to a net-zero emissions by 2050 target, declaring his position before a policy review after the party's heavy defeat at the federal election in May.
Coalition home affairs spokesman Andrew Hastie, who has declared himself as an aspirant for the Liberal leadership in the future, said he would resign from the front bench if a net-zero policy was adopted.
Cabinet and shadow cabinet ministers are bound by solidarity and must toe the party line on policy or forfeit their positions.
Mr Hastie said he had "nailed my colours to the mast" over the climate policy.
His comments came mere hours after a landmark National Climate Risk Assessment laid out a catastrophic vision of Australia's future if climate change runs unchecked.
It included a concerning uptick in heat-related deaths and ballooning risks for coastal towns as sea levels rise.
The prominent conservative's comments ratchets up pressure on Opposition Leader Sussan Ley, who has consistently said she wants to let the post-election review process play out before a decision is reached on net zero.
The government is likely to release the 2035 target in coming days after receiving advice from the Climate Change Authority, reigniting a long-running climate policy debate within the opposition.
The coalition will review the target and associated policy pathway before committing to a position, including whether an associated cost will be released, what the modelling is based on and how it compares to similar countries.
Nationals senator Ross Cadell, who sits in shadow cabinet, played down the likelihood of a massive blow up.
"I don't think it will be a brouhaha," he told AAP.
"It will be a wide-ranging and happy discussion in which we try and find a general consensus."
Nationals senator Matt Canavan, a net-zero sceptic, and Senator Cadell are leading the Nationals' review into its net-zero policy but the report has been delayed as the pair await data from external organisations.
The Liberals are conducting their own policy review.
Former Liberal MP and moderate Fiona Martin said there were so many aspects about Labor's transition plan the coalition could fight against rather than opposing net zero.
"You can't win an election in Australia without net zero," the former member for Reid told AAP.
Other moderate Liberals have branded any move away from net zero a death wish, saying the party was bleeding votes in metropolitan seats where voters cared about climate action.
Moderate Liberal Tim Wilson played down the need to reduce emissions, saying "I don't think people are stressed about us having emissions reduction".
The messaging from some Liberals looking to strike a balance has been around a commitment to net zero not coming at any cost, with frontbencher Jonno Duniam saying it was "something that only stupid people would pursue".
"If we just said net zero, at any cost, by 2050 I think you would find there would be a mass exodus," he said in reference to shadow cabinet members.
Ms Ley and her deputy Ted O'Brien appear on the same page, issuing a joint statement advocating for "credible" targets that didn't overburden households and businesses.
