Spanish firefighters were battling around 100 wildfires in the northwestern Asturias region on Sunday, where flames fed by strong winds forced the closure of roads and a rail line, officials said.

Over 230 firefighters backed by over 50 soldiers were deployed after the fires broke out on Saturday as Spain basks in unusually warm weather for the time of the year.

"The intensity of the blazes has diminished due to the intense work carried out by firefighters and the rain that fell in some areas," a local emergency services statement said.

Wildfires are unusual in December and the authorities are investigating the cause of the blazes.

The flames affected mainly the northwestern part of the region, which boasts old and elegant seaside towns and a wealth of forests and vegetation that has made it popular with tourists.

Several roads and well as a railway linking Asturias to the neighbouring region of Galicia were closed off due to the flames on Saturday but have since reopened, local officials said.

Wind gusts of up to 100 kilometres (60 miles) an hour fanned the flames.

Wildfires have destroyed more than 54,000 hectares (13,300 acres) of agricultural and forest land in Spain this year, exceeding the area burned over the previous two years combined, the agriculture ministry said after major fires broke out in the summer.