The former finance minister of France said it would be a mistake to assign climate issues to "the backburner" because action to reduce carbon emissions could strengthen economic growth as well as protect the environment.

Speaking in Paris before her first visit to Australia as IMF chief next week to attend a G20 meeting, Ms Lagarde said previous Australian governments had played an important role in international debates about climate change.

"Australia was very much at the forefront, Australia was pioneering in this field and I would hope that it continues to be a pioneer," said Ms Lagarde, who as a politician was a conservative. "I do think that climate change issues and progress in that regard are critical and are not just fantasies, they are real issues."

The IMF chief, who oversees more than $1 trillion in loan capacity, applauded Prime Minister Tony Abbott's promise to try to use his chairmanship of this year's G20 economic summit in Brisbane to produce a brief and practical communique. But she warned this would not be easy.

Mr Abbott told the World Economic Forum in Davos last month he would aim for "a communique just three pages long [concentrating on] a few key subjects because progress usually comes one step at a time''.

"I very much hope that the Prime Minister persists in his determination to keep the communique short, simple, focused and straightforward," Ms Lagarde said. "He will have a very difficult time fighting against those whose job it has been in the last five years to make it long, cumbersome, complicated and jargonic.

"My sense is that he will have a lot of support at the heads [of government] level but not much support at the 'sherpas' level, at the drafters' levels, because it has been their way of operating.

"Implementing change in that respect will be tough so I wish him the very best in doing so and I will give him my full support."

Told of Ms Lagarde's veiled criticism of the Abbott government's commitment to climate change policy, Environment Minister Greg Hunt defended its record.

"The fact the Coalition government is committed to a 5 per cent reduction in our domestic emissions by 2020, backed by the Emissions Reduction Fund, shows we take the issue very seriously," Mr Hunt said.

"Australia is committed to taking action to address climate change. We've long moved on from a debate over the science."

Despite being criticised for unwinding the previous government's hard-won pricing on carbon pollution, Mr Hunt suggested "anyone who supports tackling climate change would support repealing the carbon tax".

"As a climate change measure, the carbon tax is a failure," Mr Hunt said.

"Despite being a $7.6 billion hit on the economy, our emissions reduced by only 0.1 per cent in the first year. We can do better."

Labor environment spokesman Mark Butler said he was not surprised that "international communities [were] shocked by the Abbott government's ignorance" about climate policy.

"Much of the world, including countries such as China, America and Korea, are forging ahead with serious action on climate change while Tony Abbott is intent on sending Australia backwards," Mr Butler said. "This policy retreat on such a critical issue is embarrassing Australia on the international stage."