Two French military training helicopters have collided and crashed in a wooded area of Provence, killing five people aboard, police say.

Officials said the crash occurred between the small towns of Cabasse and Carces, in the picturesque Var region, about 50 kilometres north of Saint-Tropez.

Police cordoned off roads throughout a broad zone around the crash site, and some three dozen police and military officials were dispatched to the scene, according to a local gendarme (paramilitary police officer).

The gendarme said three people aboard one helicopter were killed and two people on the other.

Officials gave conflicting information about how many people were aboard altogether and whether anyone had survived the crash.

Debris was scattered across two large zones, but the area is uninhabited and no-one on the ground was hurt, said the gendarme, who was not authorised to be publicly named.

French Defence Minister Florence Parly was expected to travel to the region later on Friday.

A spokeswoman for the French army said the helicopters came from the army's light aviation school based in nearby Le-Cannet-des-Maures.

The school includes a special joint training program with German military pilots, and its pilots are sometimes used for firefighting operations in the area.

AP