A shallow and powerful 7.5-magnitude earthquake struck off New Caledonia on Wednesday prompting a tsunami alert and evacuations on the Pacific island, authorities said.
The Pacific Tsunami Warning Centre said that tsunami waves had been "observed" in the region but did not say where.
Residents of New Caledonia, which lies north of New Zealand, received text messages directing them to go to refuges immediately, with waves of up to three metres possible, according to the warning centre.
But people in New Caledonia and nearby Vanuatu said they did not feel the quake, and tsunami warning sirens were not immediately activated in Vanuatu.
"Hazardous tsunami waves are forecast for some coasts," the Pacific Tsunami Warning Center said, after earlier warning that the danger zone included "coasts located within 1000 kilometres of the earthquake epicentre." The epicentre was some 300 kilometres east of Noumea.
Several aftershocks were reported as the tsunami centre warned of waves of up to three metres above tidal levels for New Caledonia and Vanuatu and up to one metre for some parts of Fiji.
New Zealand authorities issued a similar tsunami warning after the quake, but that was quickly rescinded.
There were no immediate reports of damage from the initial earthquake and according to the US Geological Survey modelling, damage from the quake is expected to be minimal in terms of loss of life.