A second nationwide strike on Tuesday will disrupt French public transport amid protests across the country, in a backlash against the government's plans to make people work longer before retirement.

Unions want to keep the pressure on the government and hope to repeat the large turnout for the first national day of protest on Jan. 19.

That day, more than a million people marched in opposition to pushing the retirement age to 64 from 62 and accelerating a planned delay in the age eligible for a full pension.

"This reform is unfair and brutal," Luc Farre, the secretary general of the civil servants' UNSA union told Reuters. "Moving (the pension age) to 64 is going backwards, socially."

Only about one in three high-speed TGV trains will run on Tuesday and even fewer local and regional trains, while the Paris metro will also be seriously disrupted.

Half of primary school teachers will walk off the job, their union said, while oil refinery staff and workers across all sectors were also set to go on strike.

Opinion polls show a majority of French oppose the reform, but President Emmanuel Macron and his government intend to stand their ground. The reform is "vital," Macron said on Monday during a visit to the Netherlands, adding that it would allow the pension system to keep working.

Pushing back the retirement age by two years and extending the pay-in period would yield an additional 17.7 billion euros ($19.18 billion) in annual pension contributions, allowing the system to break even by 2027, according to Labour Ministry estimates.

Unions say there are other ways to do this, such as taxing the super rich or asking employers or well-off pensioners to contribute more.

'Non-negotiable'

The government made some concessions in the draft bill, such as setting the new pensionable age at 64 instead of Macron's campaign pledge of 65, and agreeing to a minimum pension of 1,200 euros a month for all.

Prime Minister Elisabeth Borne says the 64 threshold is "non-negotiable", but the government is exploring ways to offset some of the impact, in particular on women.

Borne said the government was looking at the impact of the reform on the additional pension rights women normally get for having children.

As protesters rally across France, lawmakers will be debating the draft bill at committee level. The unions said they were trying to convince lawmakers not to vote on the bill.

"When there is such a massive opposition (to a reform), it would be dangerous for the government not to listen," Mylene Jacquot, the secretary general of the CFDT union's civil servants branch, told Reuters.