Hundreds of firefighters on Wednesday battled to halt the spread of a wildfire in southern France that has scorched a vast area, killed one person and injured nine others.

The blaze, which started on Tuesday, has destroyed or damaged 25 homes in the southern Aude department, where some 2,000 firefighters are struggling to control the largest wildfire in France this summer.

"The fire is still very active and the situation remains unfavourable," said Lucie Roesch, secretary general of the Aude prefecture, citing drought conditions, rising temperatures and strong winds.

An elderly woman died in her home, one person is missing and two people were injured, one of whom is now in critical condition with severe burns, according to the Aude prefecture.

Seven firefighters have also been injured by smoke inhalation.

The blaze has burned some 15,000 hectares of land in less than 24 hours.

"The fire is advancing in an area where all the conditions are ripe for it to progress," Roesch said.

Planes were dropping water on the flames, but Roesch warned "this fire will keep us busy for several days. It's a long-term operation".

Camping grounds and at least one village were partially evacuated, and several roads have been closed.

"I left everything behind me," said David Cerdan, a 51-year-old who fled Saint-Laurent-de-la-Cabrerisse, where a woman in her 60s died after she refused to leave her home.

"I'm putting it into perspective. I only have material damage," said Cerdan, who lived near the victim.

Prime Minister Francois Bayrou and Interior Minister Bruno Retailleau were to visit the Aude department on Wednesday.

An investigation has been opened into the cause of the fire, said local officials.

The wildfire is the biggest in France so far in a summer which has already seen some 9,000 fires, mainly along the Mediterranean coast, according to the emergency management service.

"All of the nation's resources are mobilised," President Emmanuel Macron said on X, while calling on people to exercise "the utmost caution". (AFP)