Australian climate targets will soon be enshrined in law, with the Albanese government on the cusp of landing a significant win for a signature bill.
The legislation will also tighten up reporting schemes to track progress towards the target.
Senators were given Wednesday night to debate the bill before voting on proposed changes on Thursday.
Key crossbench senator David Pocock will back the climate bill after securing some amendments.
He told the Senate while Labor's 43 per cent emissions reduction target wasn't high enough, he would vote for the legislation.
"While I'd like to see more ambition, climate scientists would like to see more ambition, millions of Australians would like to see more ambition - 43 per cent is certainly an improvement on where we were 12 months ago," he said.
Senator Pocock said he "won't let the perfect be the enemy of the good", stressing the need to ensure the climate target was enshrined in law.
"This target will provide certainty to encourage the large-scale investment that will be needed in the transition to renewable energy," he said.
"After more than a decade of climate wars we need to bank some gains."
Opposition Leader Peter Dutton lashed out at the legislation, saying it would leave the country in the lurch.
"Our concern is that when faced with economic headwinds, rising costs of living and energy shortages, some nations will not honour their emission targets including some of our competitor nations," he told a mining conference in Canberra.
"Labor's legislation will deny the government important policy options, placing Australia in an inflexible position, when all nations need flexibility to respond to the prevailing and volatile conditions."
Mr Dutton also criticised the government's safeguard mechanism, which is aimed at 200 of the country's biggest polluters.
He said the measure was a "tax by stealth" that showed the government's distrust of industry.
But Climate Change Minister Chris Bowen said the government had a plan to reduce emissions on a sector-by -sector basis, with the safeguard mechanism only being activated by big polluters.
Despite the coalition's opposition towards the bill, it will likely pass the Senate with support from the Greens and other members of the cross bench.
Greens senator Sarah Hanson-Young indicated the bill would be passed on Thursday but chastised the government for weighing up approvals for a major coal mine expansion at the same time.
"This is happening at the exact same time as Environment Minister Tanya Plibersek has on her desk a request for the biggest expansion of a coal mine in NSW since Australia signed the Paris Agreement," she told reporters.
"Don't make a mockery of your new laws on day one. Send a message to the industry, to the market and to the Australian people you're serious about cutting pollution."
Senator Hanson-Young rejected coalition claims transitioning to net-zero faster and having more ambitious greenhouse gas targets would increase the cost of living or drive up energy prices.