The United Nations launched an appeal for 74 million US dollars Tuesday to help one million flood-stricken people in Philippines for the next six months.

Some 300 people were killed when Tropical Storm Ketsana (also known as Ondoy) slammed into the South-East Asian nation last week, displacing hundreds of thousands. It brought the equivalent of one year's worth of rain in just 12 hours, and with waters rising so rapidly, people in low-lying areas sought refuge on their roofs to avoid being swept away.

The devastation wrought by that deadly storm was amplified by Typhoon Parma, which made landfall in recent days, killing at least 16 people and affecting 70,000 others. That storm struck an area focused on agriculture, resulting in a nearly 120 million US dollars loss in crops. Pre-emptively, 35,000 people were evacuated, but the number of people sheltering camps is expected to rise to 100,000.

According to the UN Office for the Coordination of Humanitarian Affairs (OCHA), approximately 16,000 houses were destroyed by the storm and subsequent flooding, while a further 23,000 were partially damaged.

Some 400,000 people are living in emergency shelters around the hard-hit capital, Manila, 80 percent of which is inundated, and many people expected to return to their homes once the water has receded.

To jumpstart the appeal, UN Under-Secretary-General for Humanitarian Affairs John Holmes said Tuesday that he has allocated 7 million for the Philippines emergency from the Central Emergency Response Fund (CERF), set up to finance sudden-onset or under-funded crises.

The 74 million US dollars flash appeal, he said, is the largest ever for the Philippines, which is "no stranger to disasters and certainly to floods."

It was developed in partnership with the Philippines National Disaster Management Agency, and appealing organizations include UN agencies, along with the Philippines National Red Cross, the International Federation of Red Cross and others.

After one month when there is a clearer picture of humanitarian needs, the flash appeal will be revised.

The UN World Food Programme (WFP) is asking for 26 million US dollars as part of the larger 74 million US dollars appeal to fund its three-month emergency operation, already under way, to support the government's efforts by providing rice, beans and other food in the worst-hit areas of Manila and surrounding areas. The agency is also giving logistical support to allow humanitarian agencies to access remote areas.

WFP said Tuesday that it is also rushing helicopters and inflatable boats to reach flood victims in remote areas with humanitarian aid.

"Many needy people live in areas that still remain inaccessible because of the widespread flooding," said Stephen Anderson, the agency's country director in the Philippines.

Seven boats, the first of 30 requested by the government, arrived Tuesday in Manila, while two of three helicopters, also asked for by authorities, are set to land in the country Wednesday.

Without these boats and helicopters, Anderson said, "the massive government-led relief effort would not be able to reach people who are really desperate, sometimes neck-deep in water."

The UN Children's Fund (UNICEF) has identified access to drinking water as the major concern in the wake of the devastating storms, with some parts of the country having been flooded with stagnant water now for many days.

Additionally, some evacuation centres are filled beyond their capacity, raising concern over possible health risks, with cases of diarrhoea and skin diseases already being reported.

UNICEF, which is asking for nearly 13 million US dollars, has already distributed hundreds of hygiene kids, and its Executive Director Ann Veneman is set to visit Manila Wednesday to assess the situation first-hand.

The World Health Organization (WHO), which appealed for 7 million US dollars, reported that it is sending medical supplies since nearly two dozen hospitals and health centres have been damaged by flooding.