The start of a heatwave that was set to send temperatures in the area soaring to 40 degrees Celsius (104F) this weekend was complicating the task of 200 firefighters battling to bring the blaze under control.

The fire started on Thursday afternoon in the area between the inland town of Lacanau and the spectacular Atlantic beaches that are this week hosting the Lacanau Surf Pro event featuring some of the world's top surfers.

Four Canadair waterbombers were deployed from dawn in an attempt to stop the fire spreading further.

To date only five residences have had to be evacuated but local authorities have taken the preventative step of temporarily banning the public from all wooded areas in the Gironde department.

A cigarette dropped from a car on Thursday is thought to have started the blaze.

The Landes forest, which spreads across the Gironde and the neighbouring departments of Landes and Lot and Garonne, is the largest maritime pine forest in Europe.

French authorities have issued a health alert for several regions this weekend after forecasters predicted unusually high temperatures in the southwest and centre of the country.

An unexpected and sustained heatwave in the first two weeks of August 2003 left an estimated 15,000 mostly elderly people dead.