An earthquake measuring 6.1 struck in the Bismarck Sea off the northern coast of Papua New Guinea.
Residents in Madang and Wewak say they had not felt the quake which hit before midday.
There were no reports of any change in sea levels.
In 1998, two undersea quakes measuring 7.0 in the Bismarck Sea created three tsunamis that killed at least 2,100 people near the town of Aitape on Papua New Guinea's north coast.
