Firefighting helicopters dump water on a smouldering spot east of Athens, trying to extinguish the remnants of a wildfire near the Greek capital that torched residential areas killing one woman and forcing thousands of people to flee their homes.

The fire broke rapidly across several fronts reaching within hours the seaside area of Nea Makri, the historic town of Marathon and suburbs on the slopes of Mount of Penteli, which is considered one of Athens' last green lungs.

Most of the fronts had eased after the inferno had first taken hold, but officials warned against complacency, stressing that the fire was still not completely under control.

As the ground around them still smouldered, residents returned to their scorched properties, assessing the damage to their homes and their lives.

Hundreds of firefighters assisted by dozens of aircraft fought to put out the blaze since Sunday as it barrelled from a forest, off Varnavas and into Athens' northern suburbs.

But it spread too fast for any of them to reach the striken suburbs, and in Varnavas, 35 km from Athens, 78-year-old Giannis Tsiminis, said no firefighters had come at all, just the police telling them to evacuate.

He ignored their advice and fought to put out the flames himself.

"We didn’t have water, only what was coming from our garden hose, there was no water at all, not a single firefighter came," Tsiminis said. "If we left here, my house would have burned down, I couldn’t have saved it."

A few meters away, Giannis Dodos, 30, and his mother clean the ash from their balcony. They fled when the flames were already inside their garden, fearing they would return to find their home burned down.

Dodos and his family were lucky, their house was intact, surrounded by a charred landscape.

He said the area used to be full of green, dense vegetation, but that had all disappeared and they had asked the local authorities for help.

“There was no measure of fire protection, it was full of dry grass, everywhere. We had asked the municipality to take some action, but they did nothing,” Dodos said.

A drone camera shows the extent of the damage as the fire raced across the hills - Greece's National Observatory said the fire has damaged around 10,000 hectares of land. The cause of the blaze has not yet been determined.

Some experts said the fire spread so fast because of a phenomenon called spotting, where wind whirls transfer burning matter across long distances. That led to the constant creation of new fronts which later merged. - Report from Reuters