Firefighters battled wind-whipped infernos along the French Riviera coast as the flames torched vegetation on hills overlooking glitzy Mediterranean resorts thronged by summer holiday makers.

Local authorities said several firefighters were injured and one hospitalised but there were no immediate reports of deaths, unlike with similar wildfires that have killed dozens elsewhere in southern Europe, notably Portugal.

One blaze that erupted late yesterday, near the Croix Valmer resort and the yacht-filled marinas of Saint-Tropez, sent clouds of thick smoke into azure skies within view of busy beaches.

Authorities said that blaze had engulfed 650 hectares of land in one of several spots where fires prompted closure of parts of the local road network, a rail line and at one stage part of the A51 motorway in the southeastern corner of France.

Weather forecasters said strong winds would persist for another day or two days at least, heightening the risk that even spots where firefighters were close to containing the flames could fall prey to another flare-up.

The blaze had already gutted 400 hectares of coastal forest in an area dotted with homes, he said.

One of the blazes was thought to have been started by a bolt of lightning, but carelessly discarded cigarette butts are often blamed for setting tinderbox areas of the midsummer southern coast alight.

Another fire that scorched at least 800 hectares of land in the picturesque Vaucluse region further inland was believed to be under control, local firefighters said.

However a further blaze was ripping through swathes of hillside on the island of Corsica that lies off the French coast in a corner of the Mediterranean near Italy.

Upwards of 1,400 hectares of forest and woodland had already been destroyed by fire by last night, when a small number of people in the village of Mirabeau and a dozen horses were evacuated to safety, authorities said.