Greens leader Adam Bandt hasn't ruled out his party siding with the coalition to block the Albanese government's climate policy.
Mr Bandt has doubled down on his party's condition that the government commit to stopping new coal and gas projects from opening in exchange for support of Labor's overhaul of the safeguard mechanism.
The proposed mechanism would cap the emissions of Australia's 215 biggest polluters and companies that breach the limit would be forced to buy carbon offset credits or trade their emissions with other firms.
When asked if the Greens would block the legislation, Mr Bandt repeatedly refused to confirm if his party would vote with the coalition, adding his stance was "an offer not an ultimatum".
"We've moved significantly towards the government's position even though we don't agree with it," he told ABC radio on Thursday.
"We've said we are prepared to shift, the ball is now in the government's court. This key question of new coal and gas mines is proving to be a sticking point."
Climate Change Minister Chris Bowen said he didn't think negotiations would end in the legislation being blocked.
"I don't believe it'll get to that point," he said.
"We're a government of adults, mature people working in good faith across the parliament, we will get things done."
Mr Bowen said the government did not have a mandate from the Australian people to rule out new fossil fuel projects and Labor planned to keep its election promises.
"I've met with many stakeholders, some people say our policy goes too far, other say it goes not far enough," he said.
"Welcome to climate change policy."
The Greens have been slammed by the government, industry and unions, who accuse the party of grandstanding and threatening to leave the country without a functioning climate policy for another generation.
Mr Bandt said the government would be accountable to its voters in electorates where climate change was a top issue if the legislation didn't pass.
