An earthquake measuring 7.5-magnitude jolted Papua New Guinea on Monday, in the wee hours and a tsunami warning was issued.
The epicentre was near the town of Rabaul, 787 km north-east from the capital, Port Moresby, the US Geological Survey (USGS) said, with a depth of 40 km.
Nearby centre Geoscience Australia said the earthquake struck at 10.48am Sydney time but confirmed that there was no tsunami threat.
However, the Pacific Tsunami Warning Centre said tsunami waves of up to three metres above the tide level could hit the Papua New Guinea coast and the cities of Kokopo (population 26,000) and Rabaul (8000) are under radar.
Last time an earthquake measuring 9.1 M hit the region on the Boxing Day in 2004.