A warning for caution has been issued with the swelling of several rivers due to the prevailing rains.
The Irrigation Department said the water levels of Kelani, Kalu, Gin and Nilwala rivers could rise further.
Some catchment areas are already experiencing minor floods.
The inclement weather has affected 2,674 people of 641 families in Matara district.
Meanwhile, the Met department forecasts scattered rain accompanied by thunder in western, Sabaragamuwa, southern and northwestern provinces.
Hambantota district is likely to experience a rainfall of more than 100 mm, with 50 mm of rain expected elsewhere.
The eastern and Uva provinces are likely to have rains in the afternoons or night.
The Department requests the public to take adequate precautions against strong winds and lightning hazards.