The death toll in Sri Lanka from strong monsoon winds and heavy rains rose to 54, as the government announced on Tuesday new safety requirements for small fishing boats.

The Disaster Management Centre said 54 people, mostly fishermen caught in rough seas, have died since the monsoon hit on Saturday morning.

Another 17 people were listed as missing, while some 33 were injured and in hospital, the centre said.

Minister for Disaster Management Mahinda Amaraweera said many of those killed in rough seas on Saturday had been fishing in small boats without life jackets or radios when the monsoon struck.

"I am proposing laws to make it mandatory for boats to be equipped with life jackets and other safety features," Amaraweera told reporters in Colombo.

"If they had these basics, we could have reduced this loss of life," he said.

Some fishermen who had been given free life jackets following a similar tragedy two years ago had not carried them in their boats when the monsoon struck on Saturday, he said.

The minister said small boats which usually go out to sea at night and return at dawn were not regulated and did not follow safety regulations that applied to bigger craft.

The monsoon hits the country twice a year, bringing vital rain for irrigation, but also often causing loss of life and damage to property. At least 64 people were killed during the monsoon in 2011.