Australia will sign up to a second commitment to the Kyoto protocol, ahead of what the Gillard government expects will be a comprehensive global emissions agreement taking effect in 2020.
Signing the first Kyoto protocol was one of the first acts of the Labor government in December 2007, and the next phase is due to start in January 2013.
Climate Change Minister Greg Combet told a carbon expo in Melbourne on Friday that Australia backed the second round of the protocol, which is to be discussed at global climate talks in Doha in December.
But the protocol, which covers less than 15 per cent of global greenhouse gas emissions and only from developed nations, was not enough on its own, he said.
Australia will push for a broader deal to be concluded by 2015.
"From 2020 we expect all countries - including the United States, the European Union, China, Japan, India, Indonesia and South Korea - will be part of a new agreement to reduce emissions," Mr Combet said.
"This will bring all countries onto the same legal platform to reduce emissions."
Without taking action to reduce emissions, the Australian economy would face a "severe economic shock" from 2020 and it was better to tackle it now, Mr Combet said.
The federal coalition has given in-principle support, subject to the current bipartisan emissions-cut target of five per cent on 2000 levels by 2020.
"Our clear goal and intention is to be part of a further commitment period, but of course we would need to see the final terms," opposition climate spokesman Greg Hunt told AAP.
"We support the current targets, irrespective of whether a new agreement is struck, and will achieve those targets if elected."
However, the coalition is concerned domestic emissions are forecast to rise under Labor's carbon tax.
The Kyoto protocol was the first global treaty to set binding obligations on countries to cut emissions and created the world's first global carbon market.
It established a set of rules and accounting procedures for emissions, and the Kyoto market mechanisms help developed countries meet their commitments and developing countries access clean technology.
Mr Combet said there was potential to increase Australia's emissions-cut target to 15 or 25 per cent.
Signing the protocol won't affect the liabilities of companies under the Australian government's carbon price, which started on July 1.
Rather, it would give businesses greater certainty of access to international carbon markets and provide new opportunities for carbon farming, the minister said.
Greens leader Christine Milne said a more realistic emissions target would be 25 to 40 per cent.
"There's a real danger we will lock in a low level of ambition globally, and it certainly means that developing countries will see Australia trying to get a sweetheart deal," she told reporters in Melbourne.
British Secretary of State for Climate Change Edward Davey said the announcement would spur on other countries to sign.
"Having Australia on board will really help to push the second Kyoto protocol period ... as we make the transition to a new, global, legally binding deal," Mr Davey said in a statement.
But New Zealand won't be following Australia's lead, with Climate Change Minister Tim Groser saying his country stood by its existing commitments.
Mr Combet was applauded at the Carbon Expo when he described Opposition Leader Tony Abbott's anti-carbon tax campaign as "complete bulls***".
He said Mr Abbott's campaign had yielded good political dividends for 18 months but the tables had turned since the tax came into effect from July 1.