A STRONG 6.5-magnitude earthquake struck beneath the sea off Papua New Guinea today, US seismologists said.

There were no immediate reports of casualties or damage from the quake, which hit at 4.37 am local time at a depth of 43km some 120km west of the island of Bougainville in Papua New Guinea, according to the US Geological Survey.

"Earthquakes of this size sometimes generate local tsunamis that can be destructive along coasts located within 100km of the earthquake epicenter," the Pacific Tsunami Warning Centre, based in Hawaii, said in a statement.

There was no risk of a destructive widespread tsunami from the quake, which was also 248kmfrom Chirovanga in the Solomon Islands, the center said.

Papua New Guinea, which is mired in poverty despite rich mineral deposits, sits on the so-called Pacific Ring of Fire, a hotspot for seismic activity due to friction between tectonic plates.

A giant tsunami in 1997, caused by an undersea earthquake or landslide, killed more than 3500 people near Aitape, on the northwest coast of mainland Papua New Guinea.

In 2007 a tsunami following an 8.1-magnitude earthquake killed at least 52 people in the Solomon Islands and left thousands homeless.

Originally published as 6.5-magnitude quake hits off PNG