Half of Air France's long-haul flights from Paris on Friday will likely be cancelled as part of severe four-day disruptions caused by a strike called by French pilots' unions, the airline said.

The strike, which will start at midnight and end Monday at midnight, affects all French air carriers and was called in protest at proposals that could see flight crew work until 65 years of age.

Legislation voted in by France's National Assembly on November 1 would effectively end the current requirement for pilots to retire at 60, and flight attendants to wrap up their careers at 55.

Air France "expects very serious disruptions of its activity... and apologises to all passengers for this unacceptable situation," a spokesperson said.

The company said it expected half of its long-haul flights from Paris to be cancelled as well as one-in-two of medium-haul flights from all airports.

More long-haul flights could be cancelled in the following days, the spokesperson added.

Air France carries out an average of 760 flights to European destinations and 73 long-distance flights from Paris a day.

Partner airlines Brit Air, Regional, CCM, Airliner should be less affected, she said adding that the status of their flights would be announced late on Thursday.

AFP