A powerful typhoon has slammed ashore freight barges and brought heavy rains to large parts of the Philippines, killing at least one person and leaving millions without power.

The two freight barges rammed more than a dozen shanty houses in Manila bay on Monday.

Dozens of people searched for their belongings in the debris and water after many from Manila's poor Tondo district sought refuge in a basketball gym.

"The waves suddenly were so strong with even stronger winds so we evacuated immediately to safety, when we came back everything was destroyed," said Ivy Rosario, who lost her home in the tropical storm.

'Worst is over'

Tropical Storm Saola caused flooding in many areas of the country, with Manila being one of the worst hit areas. Schools across the sprawling capital were suspended, the National Disaster Risk Reduction and Management Council said.

Nearly 13,000 people were evacuated in Manila, other parts of the main island of Luzon and the central Visayas region, as rainfall reached 20 millimetres (0.8 inches) an hour, according to the council.

Tropical Storm Saola did not strike the Philippines directly but exacerbated rains from a low pressure area in the vicinity [AFP]

"The worst appears to be over, though... there will be more rains forecast today," council chief Benito Ramos told the AFP news agency.

At least one person drowned in the central province of Antique, Ramos said, adding the casualty figures could go up as more reports came in.

Saola did not strike the Philippines directly but exacerbated rains from a low pressure area in the vicinity, weather forecasters said.

On Monday morning Saola was in the Philippine Sea, 330km off the northern tip of the country. It is forecast to make landfall in Eastern Taiwan by Wednesday evening.

The Manila Electric Co, which provides power to most of the capital of 15 million people and other parts of Luzon, said more than 20 per cent of its customers were without supplies.

"We apologise for the inconvenience but be assured that we are doing our best to immediately restore power," Manila Electric said in advice to customers.

Source: Agencies