A wildfire that officials thought was under control in southwest France has reignited amid a record drought and extreme heat, possibly the result of arson, officials said today.

More than 6,200 hectares of tinder-dry forest have burned in just 24 hours in the so-called Landiras blaze, the largest of several that scorched the region last month, prompting the evacuation of 10,000 people since Tuesday evening.

It had been brought under control - but not fully extinguished - after burning nearly 14,000 hectares, before flaring up yesterday.

The government said Prime Minister Elisabeth Borne and Interior Minister Gerald Darmanin would travel to the frontline of fire-fighting efforts in the southwestern French region of Gironde tomorrow.

Following the reignition of the fires, Mr Darmanin announced more resources including more than 1,000 firefighters, nine planes and two helicopters equipped to drop water.

A firefighting aircraft sprays fire retardant over trees during a wildfire in southwest France today

No one has been injured but 16 homes were destroyed or damaged near the village of Belin-Beliet, and officials said six fire engines had been burned.

"The risks are very high" that parched conditions will allow the fire to spread further, said Martin Guespereau, prefect of the Gironde department.

"The weather is very unfavourable because of the heat, the dry air, the record drought and the fact that there is a lot of peat in the ground... the fire didn't go out in July, it went underground," he told journalists.

Minister Darmanin said investigators suspected arson may be involved.

"There were eight fires that erupted between 8am and 9am that erupted at intervals of a few hundred metres, which is extremely unusual," he said in Mostuejouls, north of the Mediterranean city of Montpellier, where another fire was raging in the Grands Causses natural park.

He added that Sweden and Italy would send fire-fighting aircraft to France within 24 hours to help.

France's Interior Minister Gerald Darmanin speaking to the media today

"It's a major fire... much more intense and fast-moving" than at the height of the Landiras blaze last month, Marc Vermeulen of the regional fire-fighting authority told journalists.

"I opened the door last night and there was (a) red wall in front of us, the sky was roaring like the ocean," said Eliane, a 43-year-old at a temporary shelter for evacuees in Belin-Beliet.

For Christian Fostitchenko, 61, and his partner Monique, waiting at a martial arts dojo in nearby Salles, it was their second evacuation of the summer from their home in Saint-Magne.

"This time we were really scared - the flames were less than 100 metres from the house," he said.

The fire was spreading toward the A63 motorway, a major artery linking Bordeaux to Spain, with thick smoke forcing the road's closure between Bordeaux and Bayonne.

France has been buffeted this summer by a record drought that has forced water-use restrictions nationwide, as well as a series of heatwaves that many experts warn are being driven by climate change.

Wildfires have also ignited in the dry hills of the southeast and even in the normally lush areas of Brittany along the coast.

Officials in western France today said a wildfire near Angers and Le Mans has burned 1,200 hectares since Monday as nearly 400 firefighters struggle to contain it.