The quake hit around 35 kilometres (22 miles) northeast of Luganville, the Pacific island nation's second-largest city, according to the USGS, which revised the magnitude upwards after initially putting it at 7.2.

There was no threat of a tsunami, according to the Pacific Tsunami Warning Center.

The quake hit at a depth of 115.8 kilometres and probably caused moderate shaking across several islands, according to the USGS.

It was unlikely that the tremor caused any fatalities or significant economic damage, it said in a preliminary assessment.

Earthquakes are common in Vanuatu, a low-lying archipelago of 320,000 people that straddles the Pacific Ring of Fire, a region of intense seismic activity.

Last month, residents on the island of Espiritu Santo were shaken by a magnitude-6.4 earthquake off the coast, but damage was minimal.