The death toll from the cyclone disaster that swept the southern Philippines has jumped above 1,000.

Reuters - More than 1,000 people are dead or missing after flash floods that ravaged the southern Philippines, the government there has said.

Some 957 people have died and 49 others are missing after tropical storm Washi lashed the southern island of Mindanao and surrounding areas over the weekend, said civil defence chief Benito Ramos.

Washi brought heavy rains that swelled rivers, unleashing flash floods and landslides that struck in the dead of night and swept away shantytowns built near river mouths.

The toll rose sharply as the bodies of people who were swept out to sea were recovered.

"They were underwater for the first three days but now, in their state of decomposition, they are bloated and floating to the surface," Mr Ramos said.

A British national was among those who died in the storm, Britain's Foreign Office said.

President Benigno Aquino flew to Mindanao today to survey the devastation by air, coordinate the relief effort, and express his condolences to the victims' relatives.

The president said the impoverished nation of 94 million people was now in a "state of calamity", his spokesman Ricky Carandang told reporters.

The southern port cities of Cagayan de Oro and Iligan were the worst affected with 579 and 279 fatalities respectively, but other areas were also hit and needed immediate aid from the national government, the spokesman said.

Authorities in both cities are preparing mass burials of unidentified bodies to address health concerns, as well as the overpowering stench from huge numbers of dead that have overwhelmed mortuaries.

With dead bodies lying everywhere, there was controversy over Cagayan de Oro authorities' decision to bring at least 20 unclaimed cadavers to a nearby landfill for temporary storage.

The disaster area, located about 800km from the capital Manila, is normally bypassed by typhoons that ravage other parts of the Philippine archipelago every year.

As a result, many residents were caught by surprise when floods suddenly hit their homes as they slept.

More than 284,000 people have been displaced by the storm with over 42,000 huddled in crowded, makeshift evacuation centres, the National Disaster Risk Reduction and Management Council said