Rescue workers on Wednesday recovered the bodies of 17 villagers buried in landslides in Sri Lanka after three days of torrential rain.

The disaster hit two small villages in Kegalle, a mountainous area northeast of Colombo, and takes the overall death toll from flooding and landslides in recent days to 36.

Sri Lanka's government has deployed troops to evacuate people living on slopes or in flood-hit areas and the navy and the air force have also been called in to help with relief operations.

About 150 people living above the landslides have been rescued, military spokesman Jayanath Jayaweera told reporters.

"Army commandos rescued all of them this morning," Jayaweera said, adding that 266 troops in total have been deployed for relief and rescue operations.

Disaster Management Centre spokesman Pradeep Kodippili said Kegalle was prone to landslides and many people living there had fled their homes after the rains.

He dismissed a tweet from the Sri Lankan Red Cross that more than 200 families were missing, saying most had been accounted for and the death toll was not expected to rise significantly.

Kodippili said 17 people have died in the landslides, with the discovery of one more body in the debris, while other weather-related incidents in recent days had claimed 19 lives, taking the overall death toll to 36.

Sri Lanka Red Cross spokesmen Mahieash Johnny told AFP that there had earlier been confusion about the number of people missing.

But Johnny said the latest updates from the scene suggested that an estimated 225 families were affected by the landslides and "most of those families have moved to four relief camps in the area".

Police said many residents had fled the tea-growing and farming area before the landslides hit.

Nearly 350,000 people have been hit by flooding in Sri Lanka and 200,000 are sheltering in state-run welfare centres.

The meteorological department said the heavy rains were caused by a depression in the Bay of Bengal and were expected to subside on Wednesday.