UK has issued an "amber" alert as France, Spain and Portugal battle wildfires amid a sweltering heatwave, which scientists say become more frequent due to climate change.

Spain's health ministry warned the
Spain's health ministry warned the "intense heat" could affect people's "vital functions" and provoke problems like heat stroke. (AFP)

France and Britain are set to suffer soaring temperatures, with a heatwave in Western Europe fuelling wildfires across vast stretches of forestland.

In southern France since Tuesday afternoon, a wildfire scorched through 8 square kilometres of pine trees just south of Bordeaux, pushing 150 residents to evacuate their homes, according to the local fire department.

Prime Minister Elisabeth Borne has urged all government ministers to be ready to deal with the consequences of the heatwave, which is forecast to last for up to 10 days.

As global temperatures rise over time, they are expected to become more intense. The previous such phenomenon to blight France, Portugal and Spain occurred in mid-June.

"We do expect it to worsen," World Meteorological Organisation spokeswoman Clare Nullis told a briefing in Geneva on Tuesday.

"Accompanying this heat is drought. We've got very, very dry soils," she said.

READ MORE: Officials warn of extreme fire risk as Europe swelters in June heatwave

'Amber' alert in UK

The high temperatures are expected to spread to other parts of western and central Europe in the coming days.

Britain issued an "amber" alert – the second-highest of three levels – which indicates that the extreme heat will have a "high impact" on daily life and people. Temperatures are forecast to hit 35C in the southeast of the country in the coming days.

So far its highest recorded temperature was on July 25, 2019 – reaching 38.7C at Cambridge Botanic Garden, in eastern England – and a UK climate official saying that the chances of a new UK record was increasing due to "strongly embedded warming".

In Spain, temperatures are forecast to keep rising until Thursday, with highs of up to 44C expected in Guadalquivir valley in Seville in the south.

Spain's health ministry warned the "intense heat" could affect people's "vital functions" and provoke problems like heat stroke. It advised people to drink water frequently, wear light clothes and "remain as long as possible" in the shade or in air-conditioned places.

Firefighters in neighbouring Portugal were combating a similar inferno, which torched some 20 km² of land in the central municipality of Ourem since last week. The blaze was brought under control on Monday but flared up again by Tuesday.

With temperatures set to climb past 40C, Portuguese Prime Minister Antonio Costa urged "a maximum of caution".

Heatwaves have become more frequent due to climate change, scientists say.

READ MORE: Spain battles wildfires amid record-breaking heatwave across Europe

Source: TRTWorld and agencies