Opposition Leader Peter Dutton says a Coalition government will dump Australia's legally binding climate target to cut emissions by 43 per cent from 2005 levels by 2030.
The move would risk Australia's membership of the Paris Agreement on climate change and follows his vow to deploy nuclear energy to reach net zero by 2050.
Energy minister Chris Bowen said the Paris Agreement was very clear that countries cannot backslide on their emissions commitments.
"At the moment, the countries outside the Paris accord are Libya, Yemen and Iran. Is Mr Dutton proposing to take Australia into that company now," Mr Bowen said.
Mr Dutton told The Australian the government's renewables goal was unattainable and "there's no sense in signing up to targets you don't have any prospect of achieving".
He pointed to the delayed renewable rollout and said nuclear power must be deployed to replace fossil fuels.
"You can't have the prime minister saying we aren't going to have coal, we aren't going to have gas and were not going to have nuclear power and we are going to keep the lights on – that's just fantasy. We now have a debate about energy which I think we can win," he said.
Shadow energy minister Ted O'Brien said the government would need to "collapse industry" to achieve its 2030 targets.
"If Labor is going to achieve its 2030 targets, which industry is it going to attack? Is it manufacturing? Is it agriculture? Is it resources," he said.
"I mean, the only way now Labor can achieve its 2030 target is to collapse industry. We will not have a bar of it from the Coalition."
Mr Dutton's comments attracted the ire of environmental groups, who called his climate plans "wildly inappropriate".
"Mr Dutton's plans would be an international disgrace and it would trash our relationships with key allies who are depending on Australia to adhere to keeping 1.5 degrees alive," Australian Conservation Foundation chief executive Kelly O'Shanasy said.
"Mr Dutton is also banking on a nuclear fantasy which Australia does not need and Australians do not want."
Climate Council chief executive Amanda McKenzie said opting out of the Paris Agreement would make Australia a "global laughing stock".
"Dutton's climate policy is a disaster, and the consequence for Australians would be more extreme heat, fires and floods," she said.
"Instead of ripping up Australia's 2030 climate targets, Peter Dutton must listen to the communities already ravaged by worsening climate disasters."
Investor Group on Climate Change (IGCC) managing director Erwin Jackson said the Paris Agreement and its emissions targets had already mobilised billions of dollars towards new clean, job-creating industries.
"Back-flipping on these commitments and withdrawing from the Paris Agreement would corrode investor confidence at a time when Australia is competing for funding for new technologies and clean industries, local jobs and training opportunities.
Mr Jackson urged all parliamentarians to stay the course and set emissions targets with the highest level of ambition.
