MANILA: At least five people were killed and seven were missing as torrential rains brought the Philippine capital to a standstill Tuesday, with floodwaters covering half the sprawling city, officials said.

More than 20,000 people fled their homes due to the rising waters while a deadly landslide buried four houses in a Manila suburb, police said.

As local television flashed live footage of rampaging rivers carrying off houses and Manila residents marooned on their rooftops, President Benigno Aquino said the government was doing everything it could to help.

"Everybody who is supposed to do something is doing what he is supposed to do," he told reporters after meeting with civil defence officials.

Schools, financial markets and most government and private offices were shut as key roadways in Manila -- a metropolis of some 15 million people -- were submerged by waters that in some areas reached neck-deep.

Residents of low-lying slums fled the huge shantytowns lining Manila's rivers and sewers for the safety of schools, gymnasiums and government buildings as the downpour generated by seasonal monsoons struck overnight.

Army trucks hauled stranded residents from their homes, while enterprising children fashioned crude rafts out of scrap wood and banana tree trunks and charged people to ferry them around.

Power was turned off in some parts of the capital as a precautionary measure as the waters seeped into electrical facilities, the city's power distributor said.

Police said the Manila landslide, caused by half a month's worth of rain falling on the capital in the past 24 hours, left a man dead and six others missing.

"The rain softened the soil and four houses were buried," Maribel Mendoza of the local public safety office said.

Six other people were rescued from under the rubble and taken to hospital for treatment, she told AFP.

Four people meanwhile drowned in nearby Bulacan, a flood-prone province near Manila, local police chief Senior Superintendent Fernando Mendez said.

Even before the latest deluge, the death toll from eight days of sustained rains had reached 53 with more than 268,000 people forced to flee their homes across the country, according to disaster authorities.

In some areas of the city, people were trapped on the second floor of their houses by the fast-rising waters, said Cora Agulan of the National Disaster Risk Reduction and Management Council.

She said there were many calls for help but in some areas it was too dangerous for rescuers to try to reach those stranded.

"The current is too strong so we have to tie our rubber boats with ropes to keep them from being swept away," she said.

Rosario Brutas, a market vendor in Bacoor, a town south of Manila, said she and her husband woke on Tuesday to discover their home already partly submerged.

"We woke up before dawn to find our bed afloat," the 32-year-old told AFP from a hospital courtyard where her family and their neighbours had taken refuge.

Bad weather from seasonal southwest monsoons has pounded Manila and nearby areas for over a week since Typhoon Saola brushed past the country's north.

But Jean Navarez from the state weather service warned that the floods could worsen as the La Mesa dam, Manila's sole reservoir, began letting off water that would swell surrounding rivers.

"If we put it in a percentage, at least 50 percent of Metro Manila is flooded," she told AFP.

"There will be heavy rainfall for the next 24 hours. The floods will increase," she added.

Government weather forecaster Bernie de Leon said that in the 24 hours to Tuesday morning, 323 millimetres (13 inches) of rain fell on the capital, compared to average monthly rainfall of 504 millimetres for August.

The civil defence office said that while some 20,000 people fled to evacuation centres overnight, many more sought refuge in relatives' homes. - AGENCIES