The government has introduced a bill on its first full sitting day that would legislate a requirement for Australia to reduce emissions by 43 per cent by 2030.
But Climate Change Minister Chris Bowen has also threatened the government will walk away from the legislation if it can't find broader support for the proposed law.
The government has already notified the United Nations of its updated climate targets, but argues writing them into law would send a strong signal to investors and other nations.
Introducing the bill to the lower house, Mr Bowen said enough time had been wasted delaying action on climate change.
"2030 is 89 months away; we don’t have long to achieve these goals," Mr Bowen said.
The legislation needs the backing of the Greens and at least one other senator to pass the upper house, unless the opposition decides to support it.
But the Greens are not committing to supporting the bill, saying the target is "weak" and will be unachievable unless the government also rules out approving any new coal or gas projects.
The Climate Change Minister said he would take on "sensible, good faith" suggestions, but he was prepared to drop the legislation if it could not be passed.
"We've been very clear that this legislation is not essential, it's desirable, it's best practice," Mr Bowen told ABC News Breakfast this morning.
"Our intention is to work cooperatively across the parliament for good climate laws."
Mr Bowen said if the government could not legislate the emissions target, it would still hold itself to that standard, which was binding under the terms of the UN Paris climate agreement.
The proposed laws would also require the Climate Change Minister to provide annual updates on its progress towards the target, as well as obliging the Climate Change Authority to provide regular advice on updating future climate targets — but it does not enforce the target.
Greens leader Adam Bandt said the government must be prepared to compromise on its bill.
"You've got roughly a third of the country voted for the government, a bit less, roughly a third voted for the opposition, and roughly a third voted for someone else," Mr Bandt said.
"Power is now shared, especially in the Senate, and we've all got to work together and that means giving a bit."