Abenhaim, general director for health, told Health Minister Jean-Francois Mattei in a letter he was tendering his resignation "given the present controversies surrounding the handling of the epidemic (of deaths) linked to the heatwave."

The letter, a copy of which was obtained by AFP, said Abenhaim, 52, would continue in his job until a successor was found.

Mattei accepted the resignation, a statement issued by the health ministry said.

Abenhaim's office had been criticised for failing to notify the government about the mounting deaths from the heatwave that hit much of France during the first half of August.

Mattei on Monday said it was "plausible" that the toll could be as high as 5,000, many of them elderly people.

But he tried to deflect the anger directed at him by claiming he had only belatedly been made aware of the situation.

"We didn't have the information and the warning signals that we should have had," he said.

"The health minister, who is before you now and who totally accepts his responsabilities, did not receive any warning signals."

Temperatures breaching 40 degrees Celsius (104 degrees Fahrenheit) gripped most of the country in the first two weeks of August in the longest and hottest heatwave in more than half a century.

Hospitals and morgues were overflowing with the bodies of heatwave victims, but it was only last Thursday -- when the heatwave in fact finally broke -- that the government instituted emergency measures to add hospital beds, hire more staff and provide more ambulances.

Abenhaim is a highly respected doctor and academic. He is on leave of absence as a professor of epidemiology at Montreal's McGill University.

TERRA.WIRE