A forest fire in eastern Spain forced 700 people to evacuate their homes and indirectly caused a brief power cut at a nuclear plant, authorities said Friday.

The fire had burned 10 square kilometres (3.8 square miles) of land in the Valencia region, its government said in a statement.

"This is one of the biggest fires in recent years," regional president Alberto Fabra said after visiting the affected area.

"The weather conditions are adverse, with high temperatures, little moisture and lots of wind."

An electrical plant was evacuated in Cortes de Palla and the resulting loss of current forced a nuclear plant in nearby Cofrentes to briefly switch to generator power before normal functions resumed, a spokeswoman for the region said.

"The nuclear plant is not in any danger. The fire is not coming near it," she said.

The fire was started by an act of negligence during the installation of solar panels in a home, the regional government statement said.

Since Thursday about 700 people had been evacuated from Dos Aguas and other surrounding villages and were being housed by local families or in shelters, the spokeswoman said.

Around 1,000 emergency personnel were working to fight the blaze, along with 28 helicopters and airplanes.

"The number of hectares burnt is more than 1,000 and all the work is focussing on preventing the fire from spreading and on channeling it towards an area where it is easier to extinguish," the government said.

It was one in a series of bush fires around Spain this year that have followed one of the driest winters for decades.

In neighbouring Catalonia to the north, the fire service said Friday it had evacuated 90 people due to a fire that had burned 700 hectares (7.0 square kilometers, 2.7 square miles) in Prats de Rei, near Barcelona.

Spanish media reported at least two other smaller fires, in the north of the Valencia region and southern Catalonia.