The Disaster Management Centre said about 1.01 million people in 22 districts of the country have been affected by the adverse weather conditions according to the latest figures available with the Department of Meteorology.
The floods have destroyed 4,593 houses and damaged another 14,649, Sri Lanka's Dailymirror reported.
The biggest damage was reported in the southeastern Badulla district, where 14 people were killed by mudslides.
Authorities have evacuated Muttur and Somapura areas in Trincomalee District as the water level of Mavilaru river, that supplies water to some regions of eastern Sri Lanka, continued to rise.
Parts of Sri Lanka experiences monsoon during this time, but many other areas not normally affected are also hit by nonseasonal rains.
In October, at least 38 people were killed when mudslides buried homes of tea plantation workers in the country's central hills.