An AFP reporter and residents on New Britain said electricity was still out and radio stations off air some 12 hours after the quake, but there appeared to be no major structural damage or loss of life.
"We didn't really have that much damage thank goodness, just ornaments falling down and that kind of thing," said Ellen Morgan, a manager at Kokopo Beach Bungalows.
Officials at the nearby port of Rabaul said there was no major damage to the facility, which was operating as normal.
Papua New Guinea's poor communications infrastructure, lack of roads and difficult terrain mean that sometimes it can be days before the full impact of a natural disaster is known.
A spokesman for the National Disaster Centre in Port Moresby told AFP they had dispatched a team to uncover the full extent of the damage.
"Assessment teams have been deployed to the area but we have not heard from them yet, so we have nothing to report."
The United Nations estimated that around 120,000 people live within 50 kilometres of the epicentre.
The terrifying quake late Tuesday sent residents running from their homes for safety and sparked fears of a tsunami.
It occurred around 11pm (1300 GMT), some 44 kilometres (27 miles) northeast of Kokopo on New Britain island, the US Geological Survey said.
"It was massive, absolutely massive. Very scary," Megan Martin, the managing director of the Rapopo Plantation Resort in Kokopo, told AFP.
Some locals reported seeing the tide recede by metres after the earthquake, but fears of a devastating tsunami do not appear to have materialised.
Kokopo is no stranger to natural disasters. It sits in the shadow of nearby Rabaul, which was devastated by twin volcanic eruptions in 1994.
Earlier this year, weeks of heavy rains killed at least nine people, with many more families left homeless without access to safe drinking water.
Papua New Guinea is well within the Pacific "Ring of Fire" a hotspot for seismic activity due to friction between tectonic plates.
Just weeks ago a 7.2-earthquake knocked items off shelves in Port Moresby -- far from the epicentre -- and was felt as far away as Australia.
A 7.5-magnitude quake hit the rugged highlands region in February 2018 that triggered landslides, burying homes and killing at least 125 people.
The risk from quake-triggered tsunamis is also a real danger in PNG.
In July 1998, an offshore tremor generated a massive oceanic surge that swamped the country's northern coast, killing more than 2,000 people.
Along the South Solomon trench, an area of the Pacific that includes Papua New Guinea, there have been more than a dozen quakes of magnitude 7.5 or more recorded since 1900, according to USGS data.