Air France will cancel up to 30 percent of its flights on Tuesday, after 20 percent of Monday's flights were cancelled, because of a pilots' strike in protest at government plans to make strikers give at least two days' notice when they plan to walk out.

The airline said in a statement it hoped to guarantee more than half its long-haul flights and 70 percent of its short flights on Tuesday.

The main pilots' union, the SNPL, said 50 percent of pilots stopped work on the first day of the strike over the government decree. Their action will run until Thursday night.

"This strike is widely backed and will increasingly be so," SNPL spokesman Louis Jobard said.

Transport Minister Thierry Mariani stood firm, saying the government would go "all the way" with legislation that would allow airlines to plan minimum services rather than finding out on the day of a strike how many staff would not come to work.

"The right to strike is there, and the right to strike will remain, but passengers will at last have some rights," Mariani told RTL radio.

The strike legislation, adopted in the lower house of parliament at the end of January, will pass to the Senate in mid-February.

At Toulouse airport in the southwest, 50 flights were axed on Monday, and airports across the country suffered delays that added to travel difficulties caused by sub-zero temperatures.

Air France shares were hit, closing down 4.14 percent at EUR€5.12, compared with a 0.14 percent decline in the European travel and leisure index.

One investment analyst, who asked not to be identified, said the strike was the first test for management since it implemented a restructuring plan. "The financial situation could rapidly get complicated if the industrial unrest were to drag on," he said.