Naval boats and helicopters scoured seas off Sri Lanka on Monday for dozens of missing fishermen, as the death toll from heavy monsoon rains and strong winds rose to 40, an official said.

The bodies of 39 fishermen along with one victim killed on land have been recovered while another 30 fishermen caught in rough seas are missing, said a spokesman for the Disaster Management Centre (DMC).

The rain and winds which pummelled the island early on Saturday have also destroyed more than 100 houses and damaged another 2,185 buildings, said the spokesman, Sarath Lal Kumara.

"We continue to look for missing people," Kumara told AFP. "The navy and the air force are leading the search-and-rescue operations."

Another 35 people were injured by the storm.

A group of Buddhist monks has lodged a protest with the Colombo meteorological office, accusing it of failing to give sufficient advance warning about the strength of the monsoon.

"Your inefficiency resulted in a national calamity," the monks said in a letter addressed to the head of the weather office. "We demand that you take every step possible to prevent a recurrence."

There was no immediate comment from the weather office, but President Mahinda Rajapakse ordered an investigation.

The president called for an early report into "why affected people were not informed of the impending severe weather conditions in order to be able to take precautionary measures". according to his office.

The monsoon hits the country twice a year, bringing vital rain for irrigation, but also often causing loss of life and damage to property.

Seven people were killed in the country last month when a tropical cyclone brushed the eastern coast.