Treasurer Josh Frydenberg has defended the federal government’s 2050 net-zero policy after French criticism and a surprising intervention from a former cabinet colleague.

Former Western Australian senator Mathias Cormann, who is now head of the Organisation for Economic Co-operation and Development, used his new role on Thursday to encourage countries to adopt more “stringent” carbon prices.

It is a dramatic turnaround from his seven years as finance minister in the Abbott, Turnbull and Morrison governments, when he once declared carbon taxes a “very expensive hoax”.

“G20 economies are lifting their ambition and efforts, including through the explicit and implicit pricing of carbon emissions,” Mr Cormann said.

“However, progress remains uneven across countries and sectors and is not well enough co-ordinated globally.”

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Mr Cormann was a senior member of the Abbott government when it ditched the Gillard government’s carbon tax in 2014. In 2011, while in opposition, he argued the Gillard government’s “push to put a price on carbon on the basis that it would help reduce global greenhouse gas emissions is a very expensive hoax”.

His conversion sparked astonishment on the opposing side of politics. Learning of the remarks during Senate estimates on Thursday, Labor senator Tim Ayres said Mr Cormann had “defined his political career by stopping climate action in Australia”.

“Are we certain that this is the same Mathias Cormann?” he said.

“Is this the same bloke?” he asked. “What on Earth is going on?”

The statement came almost as Prime Minister Scott Morrison departed Australia for a meeting of the G20 in Rome and then onto Glasgow for this weekend’s crucial COP26 United Nations’ climate talkes.

Mr Morrison’s departure on Thursday was delayed by a much anticipated call from French president Emmanuel Macron, who also urged Mr Morrison to be more ambitious on climate change.

It was the leaders’ first conversation since Australia tore up a $90 billion submarine contract with France, sparking a major diplomatic rift.

An Australian read out of the meeting said Mr Morrison spoke about his government’s recent commitment to net zero by 2050.

A French account of the call said Mr Macron encouraged Mr Morrison to adopt ambitious measures to tackle climate change.

“In particular, the ratcheting up of the nationally determined contribution, the commitment to cease production of coal at the national level and broader and greater Australian support to the International Solar Alliance,” it said.

Mr Frydenberg said the Coalition’s commitment to the mid-century goal was a significant step forward, following negotiations with the Nationals.

“We’ve shown it’s not a binary choice between reducing emissions and growing the economy,” he told Sky News on Friday.

“We have installed renewable capacity in the country faster than we have seen in other nations. We’re walking the talk when it comes to reducing emissions.”

Opposition Leader Anthony Albanese warned global leaders would have long memories of Australia’s climate change policies ahead of the Glasgow summit.

Mr Albanese said the delay in signing up to the mid-century goal could have ramifications for international relations.

“People on the global stage – they’re not goldfish. They have memories,” he said.

“We have a prime minister who has opposed renewable energy targets, who opposed net zero by 2050, who has ridiculed electric vehicles. They see that and mark Australia down.”

Labor insists it is waiting to see what comes from the Glasgow conference before releasing its climate targets.

The government has released projections showing Australia will reduce emissions by 30 to 35 per cent by 2030 on 2005 levels.

But it is refusing to lift its 26 to 28 per cent end-of-decade target.

Mr Morrison has committed to release modelling underpinning the government’s 2050 plan in coming weeks. Officials are still working on how the material is presented.

Mr Frydenberg said Treasury officials were seconded to help produce modelling for the net-zero target.

“We did provide input in relation to particular issues like risks premiums and cost of capital, were no actions taken on a net-zero target,” he said.

-with AAP