An earthquake of magnitude 7 has struck the Vanuatu region, the German Research Centre for Geosciences says, with a tsunami warning issued for coasts in the the area.
The quake was at a depth of 10km, GFZ said.
It earlier pegged the quake at a magnitude of 6.6.
The United States Geological Survey (USGS) measured the earthquake at 7.1 magnitude, with a depth of 48km.
The US Tsunami Warning System said hazardous tsunami waves from the earthquake were possible within 300km of the epicentre along the coasts of Vanuatu and New Caledonia.
The Joint Australian Tsunami Warning Centre said there was no tsunami threat to the Australian mainland, islands or territories.