"Nineteen of the 25 administrative districts in the island were affected by heavy rains, floods and earth slips. 47,922 families or 207,556 people have been affected," disaster management department's spokesman Pradeep Kodippily said.
He said 176 shelter homes have been erected to provide accommodation to more than 134,000 people affected by the rainfall over the past three days.
Emergency workers today found the bodies of a woman and two children killed in a landslide, taking the death toll from two days of heavy rain to 11. Six more were still missing.
A meteorological department official said the low pressure which caused heavy rains had now moved towards south India.
The heavy rainfall has felled trees blocking roads at a number of places, snapped power cables leading to power outages.
Sri Lankan armed forces have been put on alert since yesterday. Landslide warnings have been issued in at least eight districts.