The World Health Organisation says the first signs of potentially deadly diseases are threatening survivors in Tsunami-hit Asian areas.

David Nabarro, the top official at the Geneva-based WHO dealing with humanitarian crises, told reporters that there are increasing reports of diarrhoeal disease outbreaks coming from displaced persons' settlements in Sri Lanka and India.

However, he said these initial signs were not cause for alarm, though preventive measures and treatments must continue.

But he added it needs a few more days before WHO can state that it has been able to avoid major outbreaks of disease.