A peak business group has questioned federal government figures showing a coal-to-nuclear energy transition would cost hundreds of billions of dollars.
Energy Minister Chris Bowen seized on analysis from his department to attack the coalition's nuclear energy policy, saying it would be the most expensive form of energy and cost taxpayers $387 billion to transition.
But Australian Chamber of Commerce and Industry head Andrew McKellar said the figure raised more questions than it answered.
The departmental figures failed to take into account private sector investment and that nuclear would work alongside renewables, instead of taking on the entire load itself, he said.
"It does pose the question, why is the government not putting all of the options on the table to ensure that the Australian economy has access to an affordable, secure and sustainable supply of energy in the future?" Mr McKellar told reporters in Canberra on Tuesday.
Industry Minister Ed Husic defended his cabinet colleague, saying wind and solar power were the cheapest forms of renewable energy.
The significant upfront costs would also come on top of community concerns about nuclear power plants, he said.
"That is a huge amount of money that would be required and then the key ingredient here is community consent - where these potential nuclear power plants would be built," he told ABC TV.
"What we really need is to get focused on how we make this transition as efficient as possible."
Opposition Leader Peter Dutton said Ontario in Canada had 60 per cent nuclear power in its energy grid and residents were paying half the electricity bills of Victorians.
"I don't believe for a moment that Labor can get to zero emissions by 2050 with their current energy mix," he said.
"If Canada can do it, if France can do it, if the United States can do it, if the United Kingdom and elsewhere can do it - why can't Australia?"