The country has appealed for foreign aid to deal with the disaster, which has displaced more than 450,000 people.
Some 374,890 people are living in makeshift shelters, three times more than previously reported.
Defence Secretary Gilberto Teodoro said the situation could become worse if aid supplies run out.
The sharp rise in the death toll - up 100 from the previous figure - came after more than 90 deaths were recorded in Manila, the National Disaster Coordinating Council said in a statement.
Earlier, Mr Teodoro appealed for humanitarian assistance from the international community.
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Many people have been left with nothing but what they are wearing
"We are trying our level best to provide basic necessities, but the potential for a more serious situation is there," he said, in a nationally televised address.
"We cannot wait for that to happen."
Mr Teodoro said troops, police and volunteers had so far been able to rescue more than 7,900 people.
The UN's World Food Programme (WFP) is sending vital food supplies for 180,000 people to the Philippines.
WFP Executive Director Josette Sheeran said the organisation would support the Philippines to ensure a "swift and coordinated recovery effort".
Rescue workers are continuing to pull bodies from the mud and swollen rivers.
But the BBC's Alastair Leithead in Manila says the rescue operation is now focusing on getting supplies to those who have been displaced.
"We are waiting for more aid to arrive," said Armando Endaya, a community leader sheltering in a gymnasium in Manila with 3,000 other people.
"We are trying to mobilise our own relief operations here. But we need more help," he told AFP.
President Gloria Arroyo has said she is opening up the Malacanang presidential palace to displaced people.
"Evacuees will be given shelter in available areas among the Malacanang buildings and in tents that will be put up in between the buildings," she said in a statement.
She said that if required, palace employees would "yield their work stations to provide more space for our displaced countrymen".
Overwhelmed
On Sunday, Mrs Arroyo said the storm was "an extreme event that has strained our response capabilities to the limit".
But she said it was "not breaking" the country.
However, rescue workers are reported to be overwhelmed by the scale of floods.
The head of the National Disaster Co-ordinating Council, Anthony Golez, said resources were being spread too thinly.
"We are concentrating on massive relief operations. The system is overwhelmed, local government units are overwhelmed," Mr Golez told reporters.
"We were used to helping one city, one or two provinces but now, they are following one after another. Our assets and people are spread too thinly."
One doctor in Manila told the BBC that he had been working 24-hour shifts in a hospital flooded with water since Saturday.
The authorities were now focusing on providing food, medicine and other necessities to those in emergency shelters, he added. Telephone and power services in some parts of Manila remain cut.
Ketsana, with winds of up to 100km/h (62mph), hit the Philippines early on Saturday, crossing the main northern Luzon island before heading out toward the South China Sea.
Over the weekend, the government declared a "state of calamity" in Manila and the 25 storm-hit provinces, including many that have not experienced widespread flooding before, allowing access to emergency funds.
Officials say more than 40cm (16in) of rain fell on Manila within 12 hours on Saturday, exceeding the 39cm average for the whole month of September.
