Heavy rain pounded the Philippine capital and surrounding areas for a third day Wednesday, adding to the misery of nearly 300,0000 exhausted people displaced from their flooded homes.

Eight people have already been confirmed killed from the monsoon rains that have battered the main Philippine island of Luzon, and provincial authorities warned the death toll was likely to rise with reports of more drownings.

About one third of Manila, a low-lying and sprawling city of 12 million people, remained under water, with some areas enduring waist-deep floods, according to Philippine Red Cross secretary general Gwendolyn Pang.

The crisis had eased from Tuesday, when more than half of the city was submerged and the rain was heavier.

But Pang said many people were still suffering, with close to 300,000 people living in evacuation centres or seeking shelter with friends and relatives.

"The problem now is food, and a source of water for drinking. They also have to wash their clothes (while) some had their belongings washed away by the water," Pang told AFP.

One of the worst-affected areas was the coastal areas of Cavite, about 18 kilometres (11 miles) from the heart of the capital, where residents were enduring waist-deep water streaming through countless homes.

"We are really pitiful here. People are still shocked. There is no electricity, they are looking for food and have to walk miles to get food," Lino Ibadlit, a district councillor, told AFP.

He said the local government had brought some food and other relief goods, but they were only suitable for one day.

"This will be a long day for all of us... the people have no choice but to wade through the water to look for food, but stores are either closed or have run out of supplies... We need canned goods, noodles, biscuits."

Ibadlit said health issues were also starting to become a concern, with children beginning to suffer from colds and skin rashes.

The floods had paralysed the capital on Monday and Tuesday, with schools, government offices and the stock exchange closed. The city was even quieter on Wednesday, although it was a public holiday.

People living in important farming regions to the north of Manila were also enduring flooding.

Local governments reported that at least seven other people had died due to the floods in some of those areas.

However the National Disaster Risk Reduction and Management Council had yet to confirm the fatalities, and the official death toll remained at eight.

Moderate to heavy rains were expected to continue to fall across Manila and the northern regions of Luzon throughout Wednesday, the state weather bureau said.

The heavy rains were due to the seasonal monsoon being exacerbated by Tropical Storm Trami, which had been hovering to the north of the Philippines.

Trami was about 500 kilometres (300 miles) northeast of the Philippines on Wednesday and moving slowly away, according to the weather bureau, which said the rains were expected to ease late in the week.

The Southeast Asian archipelago endures about 20 major storms or typhoons annually, generally in the second half of the year and many of them deadly.

More than 460 people were killed in 2009 when Tropical Storm Ketsana left 80 percent of Manila submerged.

And in August last year, 51 people died when more than a month's worth of rain was dumped in and around Manila in 48 hours.