Prime Minister Tony Abbott on Monday opened the door to the use of nuclear energy as Australia faces growing pressure to reduce its greenhouse gas emissions.

Australia is the world's third-ranking uranium producer behind Kazakhstan and Canada but does not use nuclear power, largely due to its abundance of low-cost coal and natural gas reserves, and community sentiment.

But with demands growing for Canberra to announce its climate targets for beyond 2020 at global talks in France late next year, Abbott said he was open to the idea.

"On nuclear energy, as I have said on many occasions, I don't have any theological objection to nuclear," said the prime minister, who recently called coal "good for humanity" and once said climate change science was "absolute crap".

Australia is among the world's worst per capita polluters due to its reliance on coal-fired power and mining exports.

Canberra has so far committed to reducing emissions to 5.0 percent below 2000 levels by 2020. Environmentalists say it ought to target 15 percent.

A reopening of the nuclear debate in Australia comes after the United States and China -- the world's two biggest polluters -- announced a surprise deal last month to ramp up their efforts to combat climate change.

It effectively made global warming central to the world political agenda, and stymied efforts by Abbott to reduce the issue to the margins of last month's G20 summit in Brisbane.

- 'We want to reduce emissions' -

Abbott acknowledged that nuclear power was an important part of the energy mix in many countries, pointing to Japan and France.

"So I have no theological objection to nuclear energy and if we are to dramatically reduce emissions, we have to remember that the one absolutely proven way of generating emissions-free base load power is through nuclear," he said.

"It's never really been an option for Australia up till now because we don't have the energy shortages that other countries do. We've got abundant coal, abundant gas, hundreds of years of reserves of coal, hundreds of years of reserves of gas.

"We want to reduce our emissions and we will... If someone wants to put a proposal for nuclear energy generation here in Australia, fine, but don't expect a government subsidy."

Businessman and nuclear physicist Ziggy Switkowski, who headed a 2006 review commissioned by the previous conservative government that showed nuclear power was a practical option, said it must be part of the nation's energy future.

"It's a big call for our leaders to engage in this debate, but a good one because it will take some time for communities and industries to get comfortable again with the current and future generations of nuclear technology," he told the Sydney Morning Herald.

However, the Labor opposition dismissed nuclear as an energy option.

"I don't think it's a viable option for Australia," Labor foreign affairs spokeswoman Tanya Plibersek told reporters.

"We know that it's expensive. It takes a long time to get nuclear energy underway and in fact countries that have been relying on nuclear energy like Japan and Germany are actually retreating from the use of it."