Widespread flooding that turned half of the Philippine capital into a "water world" eased long enough for rescuers on rubber boats to reach many of the distressed residents still marooned in submerged villages Wednesday.

Forecasters said the monsoon rains that overflowed dams and rivers crisscrossing Manila and surrounding provinces would break for sunny weather later this week. The deluge that began late Sunday was the worst since 2009, when hundreds died in rampaging flash floods.

"We're still on a rescue mode," said Benito Ramos, who heads the government's main disaster-response agency. "Floods are receding in many areas but people are still trapped on their roofs."

Ramos had described the scene as "like a water world" after floods submerged half the sprawling capital. At least 23 people have died, including nine in a landslide in a hillside slum in suburban Quezon City and several others who drowned in outlying provinces.

More than 1.2 million people have been affected, including 783,000 who evacuated their inundated homes. Some have returned as the water was receding, but others stayed despite the hard conditions in emergency shelters as rain clouds again darkened the sky Wednesday afternoon.

Carmen Empesao said she panicked and left with her three grandchildren when waist-deep floodwaters swamped her home in the hard-hit city of Marikina.

"We fled without any food and the clothes we managed to grab were wet and cannot be worn," Empesao, 60, told The Associated Press in an evacuation centre teeming with 3,000 displaced.

Rescue efforts shifted into high gear Wednesday, with more than 130 emergency crewmen from two provinces reaching the capital city of 12 million people to help their overwhelmed teams, including police and soldiers. Rescuers used rubber boats and ropes to navigate flooded streets where many people climbed on rooftops to escape neck-deep waters.

President Benigno Aquino III distributed food packs in hard-hit communities. Traffic was light as workers tried to clear roads blocked by fallen trees and debris. he government suspended work and classes Tuesday but most offices opened Wednesday.

Ramos said he was overwhelmed by the extent of the flooding when he flew aboard a helicopter with Defence Secretary Voltaire Gazmin for an inspection. "In some areas, I could not tell the sea from the flooded villages," he told The AP.

Manila was drenched with more than half of a month's worth of rain in just 24 hours starting Monday. A typhoon that was near China and helped intensify the Philippine rains blew into the Chinese mainland early Wednesday, leading to the drier forecasts for the rest of the week.

"We may see the sun tomorrow," government forecaster Glaiza Escullar said. Sporadic downpours still were possible.

She also warned that up to three storms or typhoons could lash the Philippines this month. About 20 tropical storms are expected to affect the archipelago nation this year.

In 2009, massive flooding spawned by a typhoon devastated Manila and surrounding areas, killing hundreds.