France's under-fire Prime Minister Sebastien Lecornu said on Tuesday he would back suspending an unpopular reform that raised the age of retirement from 62 to 64 until presidential polls in 2027.

The Socialists, a key voting bloc in a fractured parliament, had said they would file a motion to oust Lecornu's new cabinet if he did not immediately suspend the measure.

In a policy speech to lawmakers, Lecornu – who is under pressure from both the hard-left and far-right blocs – supported suspending the 2023 pension reform until the next presidential election.

"There will be no increase in the retirement age from now until January 2028," he pledged.

The reform, which the government forced through parliament without a vote in 2023, sparked months of protests.

In a bid to gain opposition backing, Lecornu earlier this month promised not to force legislation through, and allow all bills to be debated in the lower house.

But he warned lawmakers that "suspending for the sake of suspending makes no sense," saying the move was an opportunity to find another path forward.

The move will cost some 400 million euros (US$463 million) in 2026 and 1.8 billion euros the year after, Lecornu said, adding the suspension must be offset by savings, not by increasing the deficit.

The former defence minister also proposed a working group to discuss the pension system, improving women's pensions and to address poor working conditions.

"This conference will have time to reach a decision before the presidential election" in 2027, he told lawmakers.

Any conclusion, he said, will then be put forward to a vote by parliament.

"The government will make suggestions, we will debate, and you will vote," Lecornu said.

Leftist parties had been threatening to join the far right and far left to oust Lecornu if he did not suspend the pension reform, but they welcomed his concession on Tuesday.

Both the Socialists and the Communists said they would not vote Lecornu out, as did the conservative Republicans who have been wary of rising spending. (Agencies)