Italian firefighterson Thursday battled hundreds of fires throughout the country's south that have killed four people, fuelled by unrelenting temperatures enveloping southern Europe.

Firefighters said there were over 500 blazes reported overnight as the anticyclone dubbed Lucifer sweeps across Italy, sending temperatures soaring and causing what is believed to be a new European record of 48.8 degrees Celsius (119.8 Fahrenheit) in Sicily on Wednesday.

The heatwave across vast swathes of the Mediterranean region in recent days began to shift west on Thursday, with many of France's southern areas put under a high temperature alert.

Spain and Portugal went on alert for wildfires as three new blazes broke out in Spain's north, even as flames continued to sweep across northern Algeria, Tunisia, and Greece -- a series of extreme weather events experts say are intensified by climate change.

The searing heat is due to continue in Italy for several days and risks fuelling fires that have already plagued much of the country's south in recent weeks, notably in Sicily and the region of Calabria.

The burned body of a 79-year-old man was found in the Reggio Calabria area on Wednesday, while another man, aged 77, died in the same region after trying to shelter his herd from the flames, news agencies reported.

Fires raging in Italy have claimed a fifth death after Sicily recorded what is believed to be a new European temperature record
Fires raging in Italy have claimed a fifth death after Sicily recorded what is believed to be a new European temperature record VIGILI DEL FUOCO / Handout

Their deaths follow those of a woman, 53, and her nephew, 35, also in Reggio Calabria, who died last Friday trying to save the family olive grove.

The fire service on Thursday morning reported making 528 interventions in the past 12 hours, 230 in Sicily, "where the situation is currently under control", including in the Madonie mountain range, near Palermo.

Regional authorities in Sicily have declared a state of emergency as a result of the fires, while 50 voluntary fire-fighting teams from around Italy have flown in to help battle the blazes.

The fire service reported 100 interventions overnight in Calabria, with particularly difficult blazes in the areas of Reggio Calabria, Catanzaro and Cosenza.

Prime Minister Mario Draghi said the government would put in place a "relief programme for people and businesses affected, along with a special plan for reforestation and securing the territory".

An anticyclone is an area of high atmospheric pressure that in summer brings dry, hot weather.

The Mediterranean has been singled out as a "climate change hotspot", with increasing temperatures and aridity lengthening fire seasons and doubling the areas potentially burnt, according to a draft UN assessment seen exclusively by AFP.