Acehnese man walks through village flattened  by Sunday's deadly tsunami in Banda Aceh

Aid agencies estimate that more than three million people may have been left homeless by the tsunami disaster, with most of them in Indonesia and Sri Lanka. Anjana Pasricha reports from New Delhi on the gigantic task that faces Indian Ocean countries in resettling these people.

Across the affected countries, volunteers, governments and aid agencies are trying to stave off hunger and disease among the millions of displaced people crowded in temporary shelters that have sprung up in schools and public buildings.

Disaster management experts say the real challenge will be to resettle these vast numbers of poor people in their villages and towns. Most of them have lost whatever they had: homes, possessions, money and a means of living. In many cases, all signs of their settlements have vanished.

Alan Bradbury with the Red Cross and Red Crescent Societies in South Asia says the task could take more than a year.

"The rehabilitation that is going to be required to get people back on their feet after this disaster is going to be a very large and ongoing challenge for everybody involved," he said.

In some countries, such as India, the focus is already turning to how to help tsunami survivors rebuild their lives. J. Gandhimati, joint secretary at India's Red Cross Society, says most of the people will have to start from scratch, especially in India's fishing communities, where boats are battered, and fishing nets are gone.

"When they go back, they need everything, roof over their head and clothing, the basic kitchen utensils and something for their livelihood," she said.

The task is most challenging in smaller countries, such as Sri Lanka, where more than one million people became homeless when the waves destroyed an entire coastline. Hundreds of villages and communities have to be resettled. More than one-fifth of the country's population is now without homes. Sri Lankan President Chandrika Kumaratunga says the country needs millions of dollars to cope.

"Our next biggest problem to which we have started giving thought is the reconstruction process, rebuilding the nation," she said. "It is going to, perhaps, cost close up on tens-of-billions of rupees. The damage to buildings, houses, vehicles and equipment is enormous."

Aid workers say the most vulnerable among these survivors are tens-of-thousands of children, many of whom may have lost one or both parents, and in some cases their entire families.

A senior official at U.N. children's fund in Colombo, Martin Dawes, says the immediate focus will be on ensuring these children survive the aftermath of the recent disaster by getting access to food, shelter and clean water. But he says special attention needs to be given to their needs in the future.

"They will need long-term help, particularly the children, because they are traumatized, and we want to restore their childhood," he said. "We want to basically be able to get them back to school, so they can talk to other children and lessen their trauma, and we want them to be back in some secure family environment."

In Sri Lanka, some grieving families who had lost their own children in the disaster are reported to be taking away orphaned children to make up for their loss. That has prompted an appeal from authorities to follow proper procedures for adoption.