"At this moment, our rough estimate sets the damage at around 925 million euros," Interior Minister Antonio Figueiredo Lopes told reporters while on a visit to some of most hard-hit areas in the centre and south of Portugal.

"Unfortunately the calamity still has not ended, fires are still burning, and this number will surely rise," he added.

Lopes was flanked by European Union Social Affairs Commissioner Anna Diamantopoulou, who arrived in Portugal on Friday to inspect damage from the fires that have so far claimed 15 lives.

Aside from the death toll, the fires have dealt a heavy blow to Portugal's forestry industry, which accounts for 11 percent of the nation's exports.

Some 162,000 hectares (nearly 400,000 acres) of woodland have been lost to flames so far this year, of which 80 percent was forest, according to preliminary forest service figures released on Thursday.

Hundreds of homes, as well as some 2,000 kilometres (1,200 miles) of power lines, have been destroyed since the fires erupted at the end of July.

The European Commission, the EU's executive arm, said earlier it would back a Portuguese request to tap into an EU "solidarity fund" designed to help member states cope with natural disasters but did not say how much money would be made available.

Diamantopoulou said the EU could make funds available immediately to help with urgent tasks such as restoring electrical power and clearing roads, but said Lisbon would have to explain how it planned to use any further aid before the EU dug into its coffers for more funds.

"The government must present proposals so we know how to employ the available money," she said. "Only then can the EU help."

The government said Thursday that Washington had also agreed to offer Portugal, one of western Europe's poorest nations, an undetermined amount of financial aid to help it cope with the fire damage.

Portuguese authorities have declared the fires a national disaster and have offered more than 100 million euros (114 million dollars) in aid to those who have lost their homes or jobs.

The aid has been criticised as insufficient but the government, which is struggling to rein in its public deficit, has said it cannot offer more.

Some 1400 firefighters, helped by hundreds of residents and 750 soldiers, were still battling fires on Friday, mostly in the centre of Portugal.

Many new blazes broke out overnight, sparked by electrical storms which swept across the centre of the country late on Thursday.

Firefighters said strong winds and extremely dry weather were fueling the fires.

With anger mounting over the destruction caused by the fires, police have stepped up their hunt for suspected arsonists.

Police on Friday detained two more people as part of their investigation into the wildfires, bringing the total number of detentions for arson in recent weeks to 35.

One of the two people arrested on Friday was a 76-year-old woman who was caught by locals setting fire to a brush near the central city of Coimbra.

Police said the woman had been convicted of arson in the past and was currently on probation.

Authorities estimate that 30 per cent of the fires which broke out in recent days week may be criminal in origin.

TERRA.WIRE