A UN Environmental Programme (UNEP) report said the tsunami had dislodged hazardous materials, causing a threat to public health, and cited Somalia, where other countries had dumped their hazardous and nuclear waste over the years.

"Somalia's coastline has been used as a dumping ground for other countries' nuclear and hazardous wastes for many years as a result of the long civil war and the consequent inability of the authorities to police shipments or handle the wastes," the report said.

"Many people in Somalia's impacted areas are complaining of unusual health problems including respiratory infections, mouth bleeds and skin conditions," it said.

The report also said thousands of wells and water sources had been contaminated in the affected countries.

The report said regions protected from the tsunami included those with thriving coral reefs, mangrove forests and other coastal vegetation as well as peat swamps.

The report summarised an environmental impact study done by UNEP at the request of the governments of Sri Lanka, Thailand, Indonesia, Maldives, Seychelles, Yemen and Somalia.