A baby was among seven people who died as torrential rains and floods swept the Greek island of Evia, damaging dozens of houses and blocking roads, authorities said Sunday.

The eight-month-old baby was found dead in a house in the village of Politika on Sunday, said a spokesman for firefighters involved in rescue efforts. The baby's parents were unharmed.

Hours earlier, a man and woman in their 80s were found unconscious by firefighters in two houses in the same village, the spokesman said. They were confirmed as dead at the hospital.

Two other people who died, a 74-year-old man and a 73-year-old woman, were from the village of Bourtsi, the ANA news agency reported.

The five dead were among an earlier official toll, which also listed one person as missing, following torrential rains late Saturday and early Sunday.

A flooded street in the village of Politika on Greece's Evia island, after torrential rains caused mass damage
A flooded street in the village of Politika on Greece's Evia island, after torrential rains caused mass damage AFP / ANGELOS TZORTZINIS

In a new toll, firefighters said seven people had died -- but gave no immediate details of who they were -- and that one person remained missing.

One woman was found after being reported missing.

The ANA news agency said a helicopter had spotted the missing woman, who had been swept away by the floodwaters from her home in Bourtsi.

Prime Minister Kyriakos Mitsotakis voiced his "profound pain for the loss of lives" and said he would visit Evia, Greece's second largest island after Crete, on Monday.

A 98-year-old woman is rescued from the storm's aftermath in Greece's Politka
A 98-year-old woman is rescued from the storm's aftermath in Greece's Politka AFP / ANGELOS TZORTZINIS

Torrents of water blocked roads in the west of Evia, which lies about 100 kilometres (60 miles) northeast of Athens. Some tourists were unable to leave one campsite on the island, ANA reported.

"We are experiencing a nightmare, we are using every possible means" to combat the floods, said Ana Fanis Spanos, a lawmaker from the central Greece region.

Storm Thalia battered several regions of mainland Greece Saturday, though the weather was improving on Sunday.

Hundreds of homes were flooded in Politika and several surrounding villages. Blocked roads prevented fire trucks from reaching the affected sites.

Two rivers burst their banks and filled roads with mud, local authorities said. The ground floors of many houses were flooded.

Manos Anastasiou, a hotel employee in Politika, told AFP how astonished he was at seeing so much rain in such a short time.

"I'm 51 years old and it's the first time I have seen something like this," Anastasiou said.

About 100 firefighters and two helicopters as well as the coastguard were deployed to rescue those trapped.

Deputy minister for civil protection Nikos Hardalias, who visited Politika Sunday morning, said more than 350 milimetres (13.8 inches) of rain fell in six hours.

"Everything happened so suddenly. It's a disaster," he said while expressing concern about climate change.

Flooded homes are a frequent occurrence in Greece due to a lack of adequate controls over construction and planning.

In November 2017, floods killed 24 people in Mandra, a village in an industrial region 30 kilometres west of Athens. Torrents of mud poured down over thousands of buildings, homes, shops and factories.