More than 800 firefighters are battling wildfires which are sweeping across central Portugal.

Two fires, which are now under control, caused the partial evacuation of a village and left 20 people injured including one in a serious condition, officials said.

Portugal's criminal police have opened an investigation on the wildfires, internal administration minister Eduardo Cabrita told reporters.

He said local authorities are interested in the fact that all the blazes started between 1430 local time (1330 GMT) and 1530 local time (1430 GMT) on Saturday around the same area.

The fires began which started on Saturday afternoon in Castelo Branco, a district 225km northeast of the capital Lisbon, and which has spread to the Santarem district.

Strong winds are making it harder for firefighters to put out the remaining wildfires although they have been able to control 60% of the flames,

"We are ready for a difficult day," Belo Costa, a Civil Protection official, told reporters but said no houses were currently at risk.

Fourteen airplanes along with 251 firefighters vehicles on the ground are also battling the blazes, as well as 20 soldiers and four bulldozers.

Carbita said 12 civilians and eight firefighters were injured in Saturday's fires. Only one is in a serious condition and remains hospitalised with first and second-degree burns.

One of the two districts affected, Castelo Branco, is under yellow alert as temperatures are expected to reach 31C on Sunday, according to the national meteorological agency.

Ricardo Aires, the mayor of Vila de Rei, one of the affected municipalities, told Portugal's public broadcaster RTP that firefighters and resources were lacking.

The Portuguese president, Marcelo Rebelo de Sousa, said in a statement that he is following the situation closely and sent solidarity to those affected.

In June 2017, a devastating wildfire in the central town of Pedrogao Grande killed 64 people and injured more than 250. The fire was the worst disaster in modern Portuguese history.