MANILA - The UN's World Food Programme said Tuesday it will provide vital rations to about 180,000 people in the Philippines that were displaced by the worst flooding in Manila in more than 40 years.

"We are deeply saddened by the magnitude of the human suffering caused by this natural calamity and we assure the Philippines Government and its people of our support for a swift and coordinated recovery effort," the agency's country representative Stephen Anderson said in a statement.

The UN will provide more than 740 tonnes of rice to flood victims in the worst-affected areas, while coordinating with the government to assess the city's other, most immediate needs, he added.

Tropical storm Ketsana unleashed 20-feet (six-metre) floods in eastern Manila and nearby areas on Saturday, killing at least 140 people and displacing nearly half a million people by the official count.

The UN agency said at least 145,000 people have been forced to flee their homes and seek refuge in evacuation centres or host communities.

Since 2006, the programme has been feeding thousands of families displaced by a Muslim separatist insurgency in the country's south.