Malcolm Turnbull has pledged Australia will follow through with its Paris climate agreement commitments, as some Liberal members welcomed Donald Trump's expected decision to withdraw from the global pact.
Mr Trump is scheduled to announce his position on Friday at 5am (AEST), with a number of media outlets quoting sources saying the US president will pull out of the 2015 deal.
NSW MP Craig Kelly, who chairs both the Liberal party and parliamentary environment committees, wrote on his Facebook page: "It's not confirmed yet but we have the champagne on ice."
Liberal senator and former minister Ian Macdonald used a Senate hearing to question why Australia should take action when the world's biggest emitter, China, appeared to be sitting on its hands.
However, the prime minister told parliament his position was the same as when the treaty was ratified in November.
"When Australia makes a commitment to a global agreement, we followed through and that's exactly what we're doing," Mr Turnbull said.
"We are committed to the Paris agreement, and we're on track to meet our targets."
Environment Minister Josh Frydenberg said any decision of the Trump administration was a "matter for them and them only, and not for us".
Mr Frydenberg noted US emissions intensity was at its lowest level in 20 years and "moving in the right direction".
Attorney-General George Brandis said Mr Kelly was entitled to his opinion as a backbencher, but Australia backed the agreement.
"We rejoice in a variety of opinions in our party room," he told a Senate committee.
The US president is expected pull the world's biggest carbon emitter from a deal which almost 200 countries have signed and 147 have ratified.
If it withdraws from the Paris Agreement, the US will join Nicaragua and Syria as non-participating parties.
Shadow environment spokesman Mark Butler said Mr Kelly's comments were cause for concern.
"I think what this indicates is a worrying sign that there will be a debate within the coalition that perhaps Australia should follow the US out of the Paris climate agreement if indeed Donald Trump pulls the US out of it," Mr Butler told Sky News.
He said China and the European Union would be expected to step up and take more of a leadership role on the issue.
"It is certainly not a catastrophe and it is also not particularly surprising given what Donald Trump said about climate change during the course of the last US presidential election."
Greens MP Adam Bandt said it just the start of the battle.
"The Trumps in the Liberal party may have 'champagne on ice' in preparation for the US withdrawal, but that ice won't be there for very long if we don't get global warming under control."
The Trump-appointed US Environmental Protection Agency administrator Scott Pruitt has publicly denied carbon emissions contribute to global warming, saying there is "tremendous disagreement" about the science.
Tesla boss Elon Musk who has pledged to fix South Australia's power issues and has advised Mr Trump, says he will have no choice but to leave the president's advisory board if the US decides to pull out of the Paris climate deal.