Shari Villarosa, the charge d'affaires in the Myanmar capital, said Wednesday in a conference call that "there may well be over 100,000 deaths in the delta area," citing an international non-governmental organization she would not name.

"It is an estimate of what deaths may actually reach, primarily in the delta area," the country's key rice-growing region where around five or six million people live, Villarosa told reporters in Washington.

She also said "95 per cent of the buildings have disappeared" in the delta area, citing a Myanmar government source.

In the capital of Yangon, Villarosa said "the government cites figures of around six or seven hundred deaths."

She said Yangon suffered mainly storm damage, with roofs ripped off buildings and electricity and water cut off.

Some water has been restored and many homes depend on pumps.

"Some electricity has been restored, including to the US embassy," she added.

Villarosa warned that staples like rice were in "short supply" and there was a "real risk" of disease because of a lack of clean drinking water.

She said UN relief teams were in the country but were far from enough to deal with the scale of the problem.