UNITED NATIONS, Jan 2: The number of survivors in need of food aid after the Indian Ocean tsunami has soared to 1.8 million people stretching from Somalia to Thailand, and the figure could rise further, the United Nations said on Sunday.

Relief teams hope to reach all of the estimated 700,000 starving people in Sri Lanka within three more days but it could take longer before enough food aid gets to nearly one million people in need in hard-to-reach parts of Indonesia, UN Emergency Relief Coordinator Jan Egeland said.

The number could go up because new assessments were in the works for remote parts of Somalia and the Maldives, a nation comprising more than 220 inhabited islands, he said.

Meanwhile, contributions to the relief effort of cash and goods now total more than $2 billion, Mr Egeland said, adding, however, that still more helicopters, trucks and other heavy equipment would be useful, "the hardware to do the moving, the shaking, the lifting".

The international aid effort had been criticized as slow to help the millions of people devastated by the massive earthquake and tsunami that hit South Asia and parts of Africa on Dec 26.

With the need so great and growing daily, the effort was still gearing up but making regular strides in assessing needs and coordinating and distributing goods and services, he said.

"Overall I am more optimistic today than I was yesterday, and especially the day before yesterday, that the global community will be able to face up to this enormous challenge," Mr Egeland told a news briefing.

"The international (relief) system is working," he said. Affected nations, working with international aid agencies, private relief groups and donor governments, were easing some early bottle necks and improving their capacity to get in goods on a daily basis to serve the estimated five million people requiring some form of aid.

Logistics centres were up and running in Rome, Jakarta and Sumatra, and a command-and-control centre set up at the U-Tapao military air base in Thailand was co-ordinating the many civil and military flights involved in the relief effort, he said.

Australia, Britain, Germany, India, Pakistan, Singapore and the United States were among governments providing civil or military aircraft, which were invaluable in quickly translating aid contributions into actual assistance on the ground.

The overall effort "is very effective, by and large," he said. "The world is really coming together here in a way that we probably have never seen before." But there were still great needs.

At the top of the list, even more important than food aid at this time, Mr Egeland said, was water and sanitation equipment, to head off expected outbreaks of water-borne diseases, spread through contaminated community water supplies.

"Diarrhoea may take as many children's lives as the tsunami in coming weeks unless we succeed," he said. UN officials say that about a third of the anticipated death toll of more than 150,000 in the disaster to date likely were children, who make up at least a third of the population of the affected countries.

In addition, assessment efforts were still lagging in northern Sumatra's Aceh province, the tsunami's epicentre, because the damage there was greatest, the region more remote and the roads in worse shape than elsewhere, Mr Egeland said.

UN Secretary General Kofi Annan was heading to the region next week to assess the damage and the relief effort and to lead a global appeal for hundreds of millions of dollars more in emergency humanitarian aid to be launched on Thursday in Jakarta, UN officials said.

At the same time, a team of aid organizations and international agencies including the UN, the World Bank and the Asian Development Bank was scrambling to assemble a plan for eventual reconstruction of the area, which would require additional billions, they said. -Reuters