French skydiver Michel Fournier readied on Monday to leap from a balloon on the outer reaches of the stratosphere and plunge 40 kilometres to earth in Canada's vast western plains.

The 64-year-old parachutist was tucked into the balloon's cabin early on Monday and was breathing canned oxygen to purge his blood of nitrogen in order to avoid suffering an embolism amid the varying atmospheric pressures up high.

He has said it is his life's dream to make the record jump, which will begin at a point four times higher than the cruising altitude of a commercial jet.

"Based on the weather forecast, he has received the green light," Bernard Desgeorges, one of the managers of the French team, told reporters shortly before 4.30am (1030 GMT).

If all goes well, Fournier should take off at 1430 GMT and climb for more than two hours in the helium balloon, reaching an altitude of 40 000 metres above North Battleford, Saskatchewan, before leaping.

During the jump, he will be wearing a pressurised suit capable of withstanding temperatures of -100ºC as he hurtles to Earth.

If he succeeds, Fournier will break four world records: for fastest freefall, longest freefall, highest jump, and highest altitude reached by a man in a balloon. It could also someday lead to rescuing astronauts in-flight.

His team leader, Richard Correa, said the moment just after take-off will be the most risky, as it would be impossible to eject during the balloon's ascent.

If Fournier loses consciousness during the jump, his parachute will automatically open.

"This project is a great scientific and human challenge," said the former French military officer. "This is my baby, my dream. I just want to realize my dream."

His latest skydiving attempt, several years in the works, comes after two unsuccessful jumps in 2002 and 2003. His balloon tore the last time, but he bought a new one for this trial.

Fournier was said to be in fighting form this round, strong as a "young man in his 20s," said Dale Sommerfeldt, launch director. Preparations for the jump were two hours behind, he said, but weather conditions were favourable, with only "very light winds."

Fournier plans to land some 40 kilometres southwest of North Battleford, Saskatchewan, where a helicopter will be waiting to pick him up.

The remote location was chosen because it is sparsely populated, and so if something goes wrong, a crash is not likely to hurt anyone on the ground.

"What he does will be remembered by the world, not just by North Battleford," said the city's mayor, Julian Sadlowski.

Before Fournier, in 1960 American Joseph Kittinger jumped from 31,333 meters as part of a medical experiment, and in 1962 Russian Evgueni Andreiev jumped from 24,483 meters to set a world free-fall record.

"This is Michael's day," Kittinger told public broadcaster CBC. "He worked a long time for this, and all we can do is wish him the best of luck."

In emails to Fournier, Kittinger said he offered the following advice: "It is a very hostile environment up there. Be certain that everything is perfect before you go."

AFP