(Reuters) - France braced on Monday for what could become one of the hottest days ever recorded with temperatures reaching 40 degrees Celsius in coastal regions cherished by tourists, as wildfires intensified in the west and south.

"The peak of this heat wave is expected Monday," MeteoFrance said in a statement, forecasting temperatures between 40 and 42 degrees - and "higher in some local areas" across France's western Atlantic coast.

"The day could become one of the hottest ever recorded in France," it said, adding that temperatures could edge towards an unprecedented 40 degrees in the Brittany port of Brest in the country's northwest.

It will become clear later on Monday whether a new national all-day average temperature record, now standing at 29.4 degrees reached from the historic heat waves of 2003 and 2019, will be set.

Thick plumes of smoke could be seen from famous Atlantic coast beaches close to the towering Pyla sand dune near Arcachon as strong winds and high temperatures kept fuelling wildfires. Interior Minister Gerald Darmanin sent three additional water-bomber planes to the region.

Fires in the region have spread over 14,000 hectares (34,595 acres), the local state prefecture said in a tweet on Monday morning, adding that there were reports of injuries so far.