Most of the deaths are reported from the Badulla district, where 16 people died when their homes were buried by landslides overnight, according to the DMC crisis center.
Water levels have risen across the country after heavy rains, and residents in low-lying areas are being urged to move to higher ground. Over 1,100 families have been moved to temporary shelters.
Over 100 millimeters of rain is expected on Thursday. According to the weather forecast, some parts of the country could receive 250 millimeters.
Monsoon rains are important for irrigation and hydroelectric power in Sri Lanka, but experts have warned that the country will suffer from increasing flooding due to climate change.
