Officials said 32 fires were out of control and a national state of emergency was declared in the central Coimbra region, where the fire was advancing on several fronts including on the outskirts of the tourist resort of Miranda do Corvo, not far from Coimbra, the parched nation's third-largest city.
Prime Minister Jose Socrates visited the affected area last night and pledged that measures to help the population would be put into effect immediately.
Police announced the arrest of three arsonists, bringing to 98 the total of pyromaniacs arrested so far this year.
Portugal is suffering one of the biggest waves of wildfires in memory as a result of a heatwave and drought not experienced since the 1940s.
A 40-year-old man taking part in the struggle to beat back the flames near Vila Nova de Poiares in the north was killed when a fire truck backed over him, police said, bringing to 14 the number of people killed in this year's blazes.
European Commission President Jose Manuel Barroso, who on Sunday visited areas affected by fires in his native Portugal where he is on holiday, praised the aid offered by EU nations to Portugal.
"We are all very impressed by the size of this problem. But it is with satisfaction that we watch European solidarity once more at work," he said to reporters in northern Portugal.
Forecasters predicted temperatures would soar above a scorching 35C in some areas, raising the risk of new fires, and remain high until at least tomorrow.
In Portugal, the fires have destroyed 134,500 hectares of land so far this year - more than in all of 2004.
The blazes have prompted calls from Spanish and French ministers for the creation of a joint European firefighting force.
