Hawaii's Pacific Tsunami Warning Centre has said an earthquake of 8.7 magnitude had occurred off the coast of Northern Sumatra in Indonesia.
The PTWC said a tsunami was generated and waves could reach Sri Lanka's coast in Trincomalee at 4.19 pm hours (1039 GMT) can the capital Colombo by 04.50pm.
Waves could reach Dondra in the South coast at 04.24 pm and Jaffna in the north at 6.05 pm.
Residents in several parts of Sri Lanka reported feeling the quake.
In December 2004 an tsunami from a much larger quake (9.6 on the Richter scale) devastated large parts of Sri Lanka.A magnitude of one indicates an increase in the size of the earthquake by 10.