Troops and rescuers dug through mud-filled houses and streets on the Portuguese tourist island of Madeira on Sunday after flash floods unleashed brown torrents which killed at least 40 people.

Portugal rushed medical teams, rescuers, divers and relief supplies to the Atlantic island. But morgue pathologists were also sent in a grim warning that more bodies would be found in the mud that swept people off their feet as they tried to escape.

The rains ended revealing scenes of devastation in the capital, Funchal, with cars overturned and roofs ripped off buildings.

Power and telephone lines were torn down but the international airport started allowing flights again from the Portuguese mainland, 900 kilometres (560 miles) to the northwest.

The regional government gave a new toll of at least 40 dead and 70 people detained in hospital.

Officials said that no foreign tourists were among the dead but the many British and German visitors seeking winter sun had been told to stay in their hotels. Britain said its diplomats were helping some nationals who were among the injured.

Seventeen dead were found in the island's main city, Funchal. Its mayor, Miguel Albuquerque, told reporters: "It is very probable that we will find more bodies."

At the height of the storm, authorities transmitted emergency messages urging people not to risk their lives by venturing out into the torrents of muddy water that poured down the hillsides and out of alleys.

Winds exceeding 100 kilometres (60 miles) an hour, high seas and blocked roads made rescue attempts even more dangerous for emergency services.

One elderly woman died when the roof of her Funchal house caved in and two others were crushed by a falling crane, local media reported.

"I only know what I see from my window," Funchal resident Margarida Freitas Vieira told the Lusa news agency describing the disaster. "The sea is all brown, there are enormous waves."

The mud filled some homes up to the second floor and the rescue teams from mainland Portugal were put to work clearing out the stricken buildings.

Portuguese Prime Minister Jose Socrates went to Funchal on Saturday night and promised "all necessary aid so that Madeira can immediately start the work of recuperating."

Football star Cristiano Ronaldo, Madeira's most famous native, said he was in shock at the disaster and promised help for relief efforts.

"It is a huge catastrophe, a tragedy without precedent," said the world's most expensive footballer, who was born in a poor district of Funchal. "No-one can remain indifferent to a calamity of such huge proportions, least of all me who was born and grew up in Madeira."

The damage was concentrated around Funchal and the Ribeira Brava region, both on the south of Madeira.

The Portuguese naval frigate Corte-Real set off from Lisbon for Madeira late Saturday with helicopters, a medical team and relief supplies, a military statement said.

Two helicopters and two C-130 Hercules transport aircraft were en route along with 89 police and firefighters.

The head of the regional government held talks late Saturday with European Commission President Jose Manuel Barroso in a bid to get EU aid.

Madeira authorities appealed for doctors and other medical staff to come in to help relieve the pressure on overworked hospital staff. They opened up a military garrison to house about 100 of the 250 people left homeless.

Officials evacuated the lower part of Funchal, which has 100,000 of the 250,000 who live on Madeira.

Portuguese media said the storms were the deadliest in Madeira since October 1993, when eight people died. Prime Minister Jose Socrates expressed shock at the deaths and promised support for the islanders.