The grouping, which includes the world's worst greenhouse gas polluters the United States and China, also threw their support behind a United Nations fund aimed at helping poorer countries deal with the problem.

"We support strong and effective action to address climate change," G20 leaders said in a communique after weekend talks in Brisbane.

"We reaffirm our support for mobilising finance for adaptation and mitigation, such as the Green Climate Fund."

The G20 talks follow a breakthrough between China and the United States on curbing carbon emissions last week, and calls from United States President Barack Obama and European leaders demanding action at the G20 on climate.

Australian host Prime Minister Tony Abbott had pushed economic issues to be the main thrust of the two-day talks, focussing on a push towards economic growth of 2.1 percent over five years and creating jobs.

Abbott, who since coming to power a year ago has dismantled a carbon tax designed to combat climate change, had resisted some language on climate proposed for the G20 communique, with one European diplomat likening the negotiations to "trench warfare".

But he insisted that climate change had been in the very first draft of the communique and were discussed throughout the year of Australia's G20 presidency.

"Obviously, it goes without saying that G20 leaders, all of us, support strong and effective action to address climate change," he told reporters.

"Our actions will support sustainable development, economic growth and certainty for business and investment and of course we will all work constructively towards the climate change conference in Paris next year."

In their declaration, G20 leaders said they aimed to support sustainable development, economic growth, and certainty for business and investment and would press for an agreed outcome in the French capital.

It also calls on members to communicate their national contributions well in advance of this meeting, preferably by the first quarter of 2015 is possible.

"Australia has always believed that climate change is real, that humanity makes a contribution and that strong and effective action against it should be taken," Abbott said, adding his government was committed to reducing harmful emissions.

But he stressed that the best way to reduce greenhouse gas emissions was more efficient energy usage.

"I don't say that there weren't at different times discussions about what is the 'mot juste' but certainly it has been a very harmonious, constructive and collegial process," Abbott said.

Japan had confirmed earlier Sunday plans to give up to $1.5 billion to the UN-backed Green Climate Fund, joining a US pledge of $3 billion to mitigate the impact of global warming on poor nations.

The GCF is a mechanism designed as a way for wealthy countries to help poorer ones to become greener and to bolster their defences against the effects of climate change.

France and Germany have pledged to contribute $1 billion each to the UN's new climate framework.

Christiana Figueres, the head of the UN Framework Convention on Climate Change (UNFCCC), has called for an initial capitalisation of $10 billion by the end of the year.