Rains have been pounding several districts of the island nation since Thursday night, and many houses, paddy fields and arterial roads were inundated.
The Disaster Management Centre said over 271,000 people have been affected by the rains in Gampaha, Ratnapura, Colombo, Puttalam, Kalutara, Nuwara Eliya, Kegalle, Kandy and Kurunegala districts.
Gampaha in the Western Province is the worst affected district with over 161,383 people affected.
So far, five people have died in Kegalle, three each in Gampaha, Ratnapura and Puttalam and one death each in Colombo, Kalutara and Galle, the DMC said.
The number of relief centres has been increased to 106.
The DMC said 26,806 people from 6,177 families have been evacuated to these camps.
Across the country, 17 houses have been completely destroyed and 978 houses partly damaged.
The Meteorology Department has warned that heavy rainfall of about 50 mm is expected.
The National Building Research Organisation (NBRO) has issued landslide warnings for six of the 25 administrative districts. The Navy was conducting rescue operations in inundated areas.