COLOMBO: Flash floods and landslides in Sri Lanka, triggered by more than three days of heavy rain, have forced more than 130,000 people to leave their homes for higher ground and killed at least 11, disaster officials said on Tuesday.

Troops have launched rescue operations in inundated areas of the Indian Ocean island, with boats and helicopters deployed to pull to safety more than 200 people trapped in the northwestern coastal district of Puttalam, officials said.

"This is the worst torrential rain we have seen since 2010," said Pradeep Kodippili, a spokesman for the country's disaster management centre, adding that many incidents were still flowing in from the 19 districts hit, among Sri Lanka's 25.

Flooded roads and fallen trees led to traffic jams in the capital, Colombo. Trains were halted as water submerged railway tracks, officials said. Families living beside rivers used boats to negotiate their way to safety.

A DMC bulletin reported a total of eight deaths, ascribing four to landslides, and one each to floods, electric shock, a lightning strike and an uprooted tree.

But it did not reflect three further deaths in a landslide in the central district of Kandy, the DMC spokesman added.

Eight people have reported missing and nine have been injured, the bulletin said.

Transport disruptions included the diversion of three Colombo-bound international flights, which went instead to Sri Lanka's second airport in its south and Cochin airport in nearby south India.

Flooding and mass displacement due to torrential rains are common in Sri Lanka.

The rains are expected to disperse slightly, weather officials said, as a low pressure area in the Bay of Bengal that brought them moves away, but strong winds will persist a few days longer.

In 2014, a landslide caused by heavy rains killed at least 16 people in a hilly tea plantation area and more than 100 went missing.

Flooding and drought are cyclical in Sri Lanka, which is battered by a southern monsoon between the months of May and September, while a northeastern monsoon runs from December to February.