Officials said 160 houses were destroyed and 194 damaged.

But rescue teams were hopeful of finding more survivors, they said.

"The area hit is very large and it's very difficult to get to some of the victims because of the mud and trees - the flash flood swept everything away," said Wathira Chotirosseranee, an official at the Interior Ministry's Civil Defence Secretariat.

"But many people managed to grab on to bamboo trees and coconut trees, and they could save themselves," Wathira told Reuters.

Wathira said the army was building shelters for the homeless and local charities were sending supplies of food, drink and clothing.

No international appeal for help was necessary, he said.

Authorities have blamed the ferocity of the flood on deforestation in the mountainous region.

On Sunday, Prime Minister Thaksin Shinawatra, a billionaire telecommunications tycoon, offered each victim of the flooding 10,000 baht ($220) from his own pocket during a visit to the devastated area.

The government has said it will give 50,000 baht to homeless families, as well as extra compensation for loss of life.