Commuters walk to get on a train at the Gare Saint Lazare station in Paris, France. French transport strikes against a planned overhaul of the pension system continue as French President Emmanuel Macron's government remains determined to push ahead with its plans. Picture: Francois Mori/AP

Paris - France was braced for massive disruption on Tuesday as moderate trade unions join hardliners for the first time in protest against President Emmanuel Macron's pension reform plans.

The renewed push by the unions comes a day after a political blow to Macron when the man he put in charge of the reform had to step down in a row about positions he held outside his government role.

With public transport still crippled on the 13th day of a strike against government plans for a single national pension system, operators are appealing to travellers to postpone their trips.

Paris Orly airport was also due to be affected, with aviation authorities telling airlines to cancel 20 per cent of their flights.

The government says the new pension system will be fairer, with everyone getting the same pension allowance in proportion to their contributions.

Hardline unions say the plans will worsen pension conditions for many workers and should be withdrawn completely.

Moderates object to a decision to raise the minimum age for retiring on a full pension from 62 to 64 for most workers.

The moderates, led by Laurent Berger of France's biggest union, the CFDT, say they will consider further action in January if the government does not concede.

But the hardliners are threatening to continue strike action through Christmas, potentially disrupting holiday travel plans.

The hardliners got more than 800,000 protesters onto the streets earlier this month.

State railway company SNCF was due, also on Tuesday, to detail its plans for the holiday season.