The United Nations said on Tuesday that at least 81,000 people in western Myanmar are homeless and in need of urgent aid after cyclone Giri hit the area last week, leaving 45 people dead.

More than 200,000 were affected and need food supplies after the tropical cyclone slammed into four western towns including Kyaukpyu in Rakhine state on October 25, destroying 15,000 houses and vital rice crops, a UN assessment team found.

"What worries us the most are the 81,000 people who are without shelter and currently need everything," said Elisabeth Byrs, a spokeswoman for the Office for the Coordination of Humanitarian Affairs (OCHA).

Myanmar's government has appealed for shelter materials, including 100,000 zinc roofing panels to ward off the heat, she added.

"The government is distributing aid with the agencies, they are working together," Byrs told AFP.

Several islands and villages around the coast have lost most of their water resources and are expected to face serious water shortages, UNICEF spokeswoman Marixie Mercado said.

UN agencies started emergency food distribution, which is expected to continue for three months.

Southwestwern Myanmar was devastated by Cyclone Nargis in 2008 which left 138,000 people dead or missing, mostly in the vulnerable river delta region.

Myanmar's military government faced international criticism for its response to the disaster two years ago after being accused of blocking emergency aid and initially refusing to grant access to humanitarian workers and supplies.

Myanmar is due to hold its first election in 20 years on November 7. Western nations have warned the vote will not be credible unless detained democracy leader Aung San Suu Kyi and other opposition figures are freed.