Some 900 hectares (2,000 acres) have been destroyed since the fire broke out Wednesday afternoon in the rugged hills of the Aude department, about 100 kilometres (60 miles) southeast of Toulouse.

Commander Philippe Fabre of the Aude fire service told AFP there had been a "slight letup" early Thursday, with firefighters able to halt the fire's advance.

But he said winds were expected to gust at up to 60 km/h (40 mph) later Thursday, and efforts would be focused on "extinguishing the fiercest hotspots and preventing flare-ups in hard-to-reach areas".

No injuries have been reported and so far no homes have been destroyed, though 22 people were evacuated from their homes in the Val-de-Dagne commune.

"Firefighters were able to stop the flames from reaching the houses but all the surrounding vegetation was destroyed. We had to evacuate the horses and donkeys," said Christian Lacube, the commune's mayor.

The cause of the blaze is not yet known, though authorities had warned of extremely dry conditions across much of southern France after weeks of drought.

"This fire is proving complicated because the areas are very difficult to access, there aren't any practicable roads," Anne Laybourne, chief of staff for the government's top official in the region, told AFP.

Three tanker planes were dropping water on the flames, with two more on standby.

Around 450 firefighters were also tackling a wildfire near Beziers  along the Mediterranean coast that began Wednesday, though officials said it was under control Thursday after burning some 250 hectares.