Fire-fighters battle wildfires that swept through homes and huge swathes of forest near Athens, forcing thousands to flee, and were beating back the main front of the inferno on its fourth day.

A dozen Greek, Italian and French fire-fighting planes tried to douse flames fanned by strong early morning winds. The operation is testing state resources, as well as a conservative government facing the threat of an early election by March.

"Air forces are operating since early morning and we hope the fire front will be controlled within the day," said Iordanis Louizos, mayor of Nea Makri, a town threatened overnight and on the fire-fighting frontline.

The fires had retreated from Athens suburbs yesterday, when authorities used loudspeakers to urge thousands to leave their communities. Flames were burning mainly forest land but strong winds were creating flare-ups, authorities said.

While thousands abandoned what are mainly holiday homes around Athens, many frantically used garden hoses and tree branches to try to stop the flames reaching their properties.

The handling of the fire, the biggest since Greece's worst wildfires in living memory killed 65 people over 10 days in 2007, will be crucial to Greek Prime Minister Costas Karamanlis.

His government is clinging to a one-seat majority and the socialist opposition, ahead in opinion polls, has made clear it will use a March parliamentary vote, when a new president will be chosen, to force a snap election.