This year's fires in Spain have already destroyed more than three times the area consumed by wildfires in 2021.

Firefighters in Spain and Portugal were battling on Wednesday to control multiple forest fires across the Iberian Peninsula with blazes in the Serra da Estrela park resuming just days after being brought under control.

Strong winds have been hampering attempts to combat the spread of the fire, one of 195 that have ravaged some 92,000 hectares of land across Portugal this year amid record temperatures.

The fire in the UNESCO-designated park restarted Tuesday after being brought under control five days earlier, and is estimated to have already consumed around 25,000 hectares (62,000 acres) of land.

More than 1,200 firefighters remained on the ground in response to the threat backed up by eight fire-fighting aircraft.

Authorities had declared some 90 percent of the park under control by midday, but fire crews are now working to "consolidate" the blaze, fire brigade commander Miguel Cruz said at a briefing.

A firefighter involved in tackling a separate blaze in central Caldas da Rainha died of a heart attack, officials said.

July proved to be Portugal's hottest in nearly a century, with the country battling its worst forest fires since 2017 when around 100 lives were lost.

Scientists say human-induced climate change is contributing to extreme weather events, including wildfires and heatwaves.

A huge wildfire thought to have been brought under control in central Portugal last week flared up again on Tuesday.

Neighbouring Spain has also been battling a wave of forest fires in recent weeks following soaring temperatures there.

The eastern Valencia region is struggling with two major blazes, one in Bejis, 70 kilometres (45 miles) northwest of Valencia city, which began Monday and has grown rapidly. It burnt up 10,000 hectares of land and forced the evacuation of 1,500 people, regional officials say.

But the weather offered some respite some 200 kilometres further south when a storm broke over the Vall de Ebo where hundreds more firefighters have been tackling another major blaze since Saturday.

As rain and hail pummelled the area where the flames have devastated more than 11,000 hectares, all 30 aerial firefighting teams were grounded, although it raised hopes the wet weather could dampen the surging flames.

Portugal's largest conservation area

In Portugal, the Serra da Estrela fire started on August 6 outside the central town of Covilha with authorities deploying 390 fire engines and 14 planes and helicopters in efforts to control it.

Firefighters, who hope to keep the fire from spreading further before temperatures rise again on Friday, have thrown a 160-kilometre cordon around the area.

So far this year, Spain has suffered 391 wildfires, destroying a 271,020 hectares of land, according to the European Forest Fire Information System.

Residents in Orjais village in the foothills of the mountain range helped fight back the flames which came dangerously close to their homes.

"It was chaos", Fatima Cardoso, 62, told AFP.

Authorities are concerned about the impact of the fire on wildlife, as Serra da Estrela is Portugal's largest natural conservation area known for its diverse wildlife, including wildcats and lizards.

"We have not yet reached the end of this critical period for fires," Interior Minister Jose Luis Carneiro warned after meeting with meteorologists.

The upcoming heatwave is forecast to last into September, which Carneiro said was set to be drier and hotter than usual.