The devastated port cities of Cagayan de Oro and Iligan in Mindanao island accounted for most of the deaths, the agency said.

The head of the government's disaster response agency, Benito Ramos, said their own count stood at 516 deaths and 274 missing. But he conceded that the death toll would likely go higher.

US 'ready' to help Philippines after deadly storm
Washington (AFP) Dec 17, 2011 - US Secretary of State Hillary Clinton sent condolences to the Philippines Saturday after more than 600 people were feared killed in a storm, and said the United States stood "ready" to help.

Relief workers said that 440 people had died and nearly 200 left missing after tropical storm Washi wreaked havoc in the southern Philippines, unleashing mammoth floods across vast areas of the country and destroying whole neighborhoods.

"On behalf of President (Barack) Obama and the people of the United States, I want to send my deepest condolences for the devastation and loss of life caused by flooding from Tropical Storm Washi," Clinton said in a statement.

"The US government stands ready to assist Philippine authorities as they respond to this tragedy."

The top US diplomat said "our thoughts and prayers are with all of those affected."

About 20,000 soldiers have been mobilized in a huge rescue and relief operation across the stricken north coast of the island of Mindanao, where the major ports of Cagayan de Oro and Iligan were worst hit.

President Benigno Aquino expressed concern at the extent of the tragedy and ordered government agencies to map out areas in the country most vulnerable to future flash floods.

Thirty hours after the floods pulverised the city of Cagayan de Oro, the undertaker's stocks of embalming formaldehyde are low and small-size caskets have gone entirely due to the sheer number of child victims.

"We are swamped. I only have five embalmers. It takes an average of four hours for each body but we have 200-plus bodies," a bleary-eyed Lacson, wearing only a basketball jersey and bermuda shorts, said on Sunday.

Frequent power cuts and the lack of tap water are the other problems his business, the Bollozos Funeral Parlour, has to deal with after the onslaught of tropical storm Washi.

The parlour's hallways are filled with bodies stacked up like logs. Many look as if they are starting to decompose in the tropical humidity, the bodies full of rancid floodwater. The reek is vomit-inducing.

Leonardo Vicente Corrales, one of many journalists reporting on a disaster that has claimed more than 500 lives across the south, counted 60 bodies at the rival Somo Funeral Parlour and 70 at another, called Cosmopolitan.

Officially, the Philippine Red Cross has tallied 248 fatalities in Cagayan de Oro from the floods, but says hundreds more people are missing overall.

Sixty percent of the bodies at Bollozos have not been identified or claimed, Lacson said, and they could become a health hazard soon.

Vicente Emano, the mayor of Cagayan de Oro, a port city of half a million people, said he recognised the threat.

"I believe the city death toll would eventually reach about 500," he said on Manila radio station DZMM in a telephone interview.

"The problem is, some mortuaries are starting to refuse them," he said.

"We're looking for a place to put all the recovered bodies."

City assistant health officer Joselito Retuya suggested to AFP that most could end up in a common pit.

"After we have identified all the dead bodies, we may have to arrange for a mass burial."

Some of the city's dead came from a shantytown called Isla Delta, which lies on a sandy bank near the mouth of the Cagayan river, nestled beneath a wall of giant billboards.

Mother-of-four Evangeline Quider told AFP the neighbourhood had 30 dead and 100 missing after the rampaging river flattened rows of slum homes made of wood and corrugated metal roofing sheets, including her family's hovel.

"We were sleeping and when we awoke, the water was already waist-deep. We immediately fled from the house, we had to climb up a billboard to reach higher ground," she said.

From there the family witnessed the deluge. Some houses were torn apart by floating debris, she said.

Venus Torres, a 48-year-old vendor, saw a sister, three nieces, and a granddaughter drown inside their shared house in the neighbouring slum called Isla de Oro.

She barely made it out alive by punching a hole through the roof of her home.

"We are used to having floods that are ankle or knee-deep. They (her relatives) did not evacuate," Torres said.

Quider, 42, used torn bits of wood from the wreckage to build a fire.

"All I have is wet rice. We can still eat it," she said.

Neighbours drew water from the brownish river to wash their flood-soiled clothes, while children huddled in one area.

Local benefactors trucked in tap water and porridge, which the shantytown survivors gratefully lapped up.

"We will still live here. We will just pick up some scrap wood and build a shack," Quider said.