The Meteorological Office in Vanuatu says a strong earthquake overnight centred near Efate was widely felt but appears not to have caused any damage.
A spokesperson Ian Huri says his office graded the shake at 7.1, up from 6.9 reported by the US Geological Survey.
He says the quake struck just after midnight west of the island of Efate and woke most people.
"It probably lasted a few seconds. It did get people out of their beds. Early in the morning we received calls from mostly people around Efate, which the earthquake was located nearby."
Ian Huri says his office received calls from some outer islands but there was no tsunami warning issued.