A huge wildfire fanned by strong winds cut a swathe of destruction near Athens, burning houses, razing large patches of forest and sending thousands fleeing their homes.

Efforts to fight the blaze from the air were suspended as night fell and the fire raged unchecked for a third day.

‘The constant shift in the wind's direction is rekindling the flames,’ said fire brigade spokesman Giannis Kapakis.

Authorities said the fire had retreated from Athens suburbs and was burning mainly forest land, but winds remained strong and the danger for a flare-up was constant.

Earlier, local authorities used loudspeakers to urge the 20,000 residents of affluent Athens suburb Aghios Stefanos to leave as the flames approached.

Many people abandoned communities around Athens overnight and some frantically tried to stop the flames reaching houses with garden hoses and tree branches.

The fire is the biggest since Greece's worst wildfires in living memory killed 65 people over 10 days in 2007.

In eastern Attica the flames seared about 30,000 acres of forest, farm fields and olive groves.

Two Italian aircraft have joined fire fighting efforts and more were expected from France and Cyprus.

The Greek weather service warned that winds hindering fire fighting efforts were not expected to abate before tomorrow night.

Police and witnesses said scores of homes were heavily damaged.

The fire broke out late on Friday in the village of Grammatiko about 40km northeast of the Greek capital and quickly spread to neighbouring villages.