Some 1.5 million people have been "severely affected" by the Nargis tropical cyclone that hit Myanmar at the weekend, a UN official said on Thursday.

Cyclone Nargis hit Myanmar last Saturday, devastating large parts of the country. The death toll, which currently stands at over 100,000, is likely to rise further as rescue workers struggle to reach remote settlements, while the nationwide number of displaced people could reach millions.

John Holmes, the UN Under Secretary General for Humanitarian Affairs and Emergency Relief Coordinator, said the situation in the disaster-stricken country is extremely dangerous and the risk of epidemic is very high due to unsanitary conditions caused by rotting carcasses and corpses in towns and villages, as well as a lack of clean drinking water.

A state of emergency has been introduced in the five worst-hit areas - the Irrawaddy delta, the cities of Yangon and Pegu, and the states of Karen and Mon. Most of the deaths came in the low-lying Irrawaddy delta region.