The US Geological Survey said the epicentre was about 50 kilometres (31 miles) west of the village of Port Olry, on the island of Espiritu Santo.

There was no risk of a tsunami from the quake, which shook the island nation just before 1:30 pm (0230 GMT), the Pacific Tsunami Warning Center said.

Angelic Frank, a staff member at a beachfront resort in Port Olry, said the quake was "very big" and seemed to last for about a minute.

There was no apparent damage in her immediate area, she told AFP.

"The plates and the cutlery rattled for quite a long time but nothing fell to the ground," she said.

"Some people here were worried but it seems everything is going to be OK."

Earthquakes are common in Vanuatu, a low-lying archipelago of 320,000 people that straddles the seismic Ring of Fire, an arc of intense tectonic activity that stretches through Southeast Asia and across the Pacific basin.