According to humanitarian organisations on Tuesday, the risks of child trafficking grows in a crisis situation where there are population movements and where the environment that normally protects the child collapses.
Unicef's spokesman in Geneva, Marc Vergara, said: "There are no parents, no family, no school, no village."
The children's fund has yet to establish exactly how many children are having to cope on their own after the massive waves killed nearly 150,000 people and obliterated entire communities throughout the region.
However, the organisation estimates that as many as 1.5 million youngsters were affected in one way or another by the catastrophe.
On average 39% of the population in countries hit by the devastating waves is aged under 18.
Cause for concern
Few cases of child trafficking have been confirmed so far, but the tragedy affected the part of the world most at risk from networks eager to exploit children for criminal ends.
Their fate includes possible slavery, prostitution, clandestine adoption and even recruitment into armed groups for use as child soldiers.
Rampant population growth, poverty and porous frontiers have made Asia especially attractive for traders in children, especially as few of the victims have been registered at birth in rural communities.
"It is easy to say: 'He is my little nephew,'" said Vergara. Even without the presence of predators, such as local mafias, it would be easy for a child, especially a girl, to be lured into prostitution "because they have to survive and because they have nothing else to offer," he said.
To protect these children, Unicef is setting up reception centres which try to identify them and to find their families, using photographs.
In rich countries there have been calls, notably in Italy and France, to make the process of adopting child victims of the Asian disaster easier.
But humanitarian organisations say that many international adoption networks are controlled by traffickers and that an orphan's best chance is to be taken in either by its extended family or by the wider village community.
"If a child has already lost everything, we feel there is no point in making things worse by imposing a new country, customs, and language on it"
Unicef spokesman on international adoption offers
If neither of these solutions is possible, the organisations say it is still best if the child remains in its home country.
"If a child has already lost everything, we feel there is no point in making things worse by imposing a new country, customs, and language on it," said Vergara, adding that he was not against international adoption in theory.
But he added: "It is not because a child has been separated that he is necessarily an orphan."
Humanitarian organisations such as Unicef, the Red Cross and Save the Children have together agreed on a common policy stipulating that a child should not be adopted abroad unless it has been clearly established that it has lost its parents and family and that there is no local community able and willing to look after it.
There should be a delay of at least two years to make absolutely certain that the child's family no longer exists, they say.