The speaker of France's parliament said Wednesday she would block an attempt to repeal a recent law raising the retirement age which was enacted after months of protests.

Speaker Yael Braun-Pivet, who is from President Emmanuel Macron's party but is officially neutral, confirmed she would reject the bid to introduce new legislation on constitutional grounds, infuriating its backers.

Speaking to BFM television, she said an amendment proposed by the small LIOT faction in parliament and backed by left-wing parties would be declared "inadmissible".

"I'm applying the rules and nothing but the rules," she added.

She was alluding to Article 40 of the constitution which bans legislative proposals from MPs that would add a burden to the public finances.

A protestor holds a sign reading "Macron's pensions, it's no !" during a demonstration in the 14th day of action after the government pushed a pensions reform through parliament without a vote, using the article 49.3 of the constitution, in Paris on June 6, 2023. (Photo: AFP)

Reversing the increase in the retirement age to 64 from 62, the key measure of Macron's hard-fought pension reform, would add billions to government spending.

Opponents of the pension reform had seen LIOT's parliamentary manoeuvre as their last hope of thwarting the changes, having previously tried and failed with an appeal to the country's constitutional court.

Observers said the minority government risked losing a vote on the LIOT legislation, however, with left-wing parties, the far right and some centre-right MPs prepared to vote against the executive.

The original legislation was rammed through the lower house National Assembly without a direct vote using a controversial constitutional power that can be invoked by the prime minister.

The move led to accusations that Macron was riding roughshod over French democracy and public opinion, with around two-thirds of voters opposed to the changes, according to polls.

LIOT called the speaker's decision to block its proposal "an unprecedented attack on the rights of parliament".