Relentless rains submerged half of the sprawling Philippine capital, triggered a landslide that killed nine people and sent emergency crews scrambling to rescue tens of thousands of residents.
The deluge, the worst to hit Manila since 2009 when hundreds died in rampaging flash floods, was set off by the seasonal monsoon that overflowed major dams and rivers in the city and surrounding provinces.
Manila and other parts of the country already were saturated from last week's Typhoon Saola, which battered the capital and the north for several days before blowing away Friday. That storm was responsible for at least 53 deaths.
"It's like a water world," Benito Ramos, head of the government's disaster response agency, said on Tuesday.
He said that the rains flooded 50 per cent of metropolitan Manila on Monday evening, and that about 30 per cent remained under waist- or neck-deep waters Tuesday.
He urged residents in areas prone to landslides and floods to stay in evacuation centres. Because the soil is saturated, even a little rain could be dangerous, he added.
Manila's weather bureau said a tropical storm off eastern China had intensified monsoon rains in the Philippines, which were forecast to last until Thursday.
In Manila's suburban Quezon City, a landslide hit a row of shanties perched below a hill, burying nine people, according to Ramos.
Army troops and police dug frantically to save those buried, including four children, as surviving relatives and neighbours wept. All the victims were recovered, some whose bodies were found near an entombed shanty's door as they apparently tried to flee.
National police chief Nicanor Bartolome went to the scene and ordered all other slum dwellers to be evacuated from the still-soggy area.
TV footage showed rescuers dangling on ropes to bring children and other residents to safety from flooded houses across the city. Many residents trapped in their homes called radio and TV stations desperately asking for help.
President Benigno Aquino III called an emergency meeting of Cabinet officials and disaster-response agencies. He ordered officials to make sure all residents were accounted for in flooded villages and discussed how flooded hospitals could be helped in case they were hit by power outages.
In 2009, massive flooding spawned by a typhoon devastated Manila and surrounding areas, killing hundreds. The state weather bureau said that the current flooding was not as severe and that the weather may start to improve later this week.