More than 1,000 people are missing in the Philippines after deadly floods, the government said Friday, doubling the feared death toll as relief groups rushed in aid for desperate survivors.

Water and toilets are urgently needed to head off potential epidemics, while survivors of the the weekend disaster require more temporary shelters, said Angela Travis, a local spokeswoman for the United Nations Children's Fund.

"The water situation is still difficult and we are worried about what this means for their health," Travis told AFP, with firetrucks having to distribute water after taps were damaged.

She said those sleeping in schools also faced "the likelihood of a secondary displacement" once classes resume after the Christmas holidays.

Nearly half a million people were affected by floods wrought by tropical storm Washi, UN agencies say, leaving nearly 50,000 at evacuation centres and thousands of others forced to live with relatives or on the streets.

As weary survivors of a disaster that swept away coastal shantytowns prepared for a bleak Christmas, authorities said there were now 1,079 people missing after the weekend's deluge, leaping from 51.

The confirmed death toll meanwhile rose to 1,080 from 1,010, more than half of them from the major port cities of Cagayan de Oro and Iligan.

The crisis prompted President Benigno Aquino to appeal Friday for the nation of 94 million to help the devastated south as Filipinos prepared for lengthy Christmas holidays.

"I have only one request to each one of you: let us not hesitate in showering them with gifts and acts of kindness," he said in a videotaped Christmas message.

With fears mounting over the health risks of unsanitary conditions, Oxfam said it will install latrines to compliment the near 200 portable toilets that Unicef has pledged to deliver to evacuation centres on Sunday.

"They're (the victims) resorting to unhygienic practices like not washing hands, which could lead to outbreaks of diseases," Oxfam country director Snejal Soneji told AFP.

The UN, which launched a $28.6 million aid appeal on Thursday, likened the force of the disaster to that of a tsunami.

The UN refugee agency on Friday airlifted the first batch of 42 tonnes of emergency shelters, blankets, and kitchen items to Manila for distribution in the flood areas.

The big jump in the number of missing came as rural families reported large numbers of relatives who had gone to work in the two cities worst hit and remained unaccounted for, civil defence official Ana Caneda said.

She said survivors who were recovering from shock or injuries have also only just realised that they have missing family members.

However, civil defence chief Benito Ramos told AFP that the list was "just an estimate" and that no one could say for sure how many people had really been lost.

Authorities have warned that many of the dead may never be found after being swept into the sea as Washi brought heavy rains, flash floods and overflowing rivers -- striking as slum-dwellers slept.

Among the missing is rickshaw driver Gilbert Olano, whose grainy photographs bearing his name, age and relatives' contact numbers were being posted across Cagayan de Oro by his wife Arlene Olano, 41.

"How can we celebrate Christmas without my husband?" the mother-of-three told AFP.

The family, among the many poor migrants who put up shacks in low-lying areas over the past decade, saw their house in the Tibasak shantytown swallowed up and taken away by the rising river before dawn Saturday.

The area is now an empty field of mud, with armed police guards stationed to stop survivors from rebuilding in an area deemed too dangerous.

"I don't ever want to go back there. I hope the government will make good on its promise to relocate us," said Olano, who said the family had to line up for food rations after being left with nothing but the clothes they were wearing.

"Sometimes it takes an hour. Sometimes we run out of food because the menfolk jump the queue. What can I do? I am just a woman."

Ramos, the civil defence chief, warned there would be no immediate relief as relocation sites were not ready as yet.