A 7.1 magnitude earthquake hit off Papua New Guinea, the US Geological Survey said, a day after a 6.7 magnitude tremor in the region.

The quake hit at 9.06am Irish time, 689km northeast of the Pacific nation's capital Port Moresby, in the New Britain region at a depth of 53km.

There were no tsunami warnings, the Pacific Tsunami Warning Centre said.

A 6.7 magnitude quake hit the same region yesterday, 131km southwest of Kokopo, but there were no reports of serious damage.

"This is the second earthquake that has occurred in that region over the last two days," co-director of the Joint Australian Tsunami Warning Centre Daniel Jaksa told AFP.

"The previous one was about 10km to the southeast of this particular epicentre. It's a very uninhabited region off the island of New Britain.

"The earthquake was a measure of 7.1, so that's about 30 times smaller than the earthquake in Nepal.

"It should be like the one yesterday - no real impact."

New Britain, the largest island of the Bismarck Archipelago, is east of mainland New Guinea and has a population of around 500,000 people.

The island lies on the 4,000km long Pacific Australia plate, which forms part of the "Ring of Fire," a hotspot for seismic activity due to friction between tectonic plates.