Firefighters battled for a third day on Thursday to contain France's biggest wildfire in nearly eight decades, which has burnt over 16,000 hectares, killed one person and destroyed dozens of houses.

TV images showed plumes of smoke rising over the forest area in the region of Aude in southern France.

Drone footage showed large swatches of charred vegetation.

French officials said one person has died, three are missing and two people including a firefighter are in critical condition.

"As of now, the fire has not been brought under control," Christophe Magny, one of the officials leading the firefighting operation, told BFM TV.

He hoped the blaze could be contained later in the day.

The blaze, around 100 kilometres from the border with Spain, not far from the Mediterranean Sea, began on Tuesday and has spread rapidly.

It has already swept through an area one-and-a-half times bigger than Paris.

Officials have said it is France's biggest wildfire since 1949.

Scientists say the Mediterranean region's hotter, drier summers put it at high risk of wildfires.

France's weather office has warned of a new heatwave starting in other parts of southern France on Friday and due to last several days. (Reuters)