"Widespread" and "hazardous" waves are possible after a magnitude 7.7 quake hit off the Solomon Islands , authorities have warned.
Among the countries most at risk are the Solomon Islands themselves, Vanuatu, Papua New Guinea and several other low-lying Pacific islands.
The Pacific Tsunami Warning Centre also said it was trying to get information about whether Hawaii was at risk.
The quake hit 70km from the Solomon Islands, according to the United States Geological Service.
The warning centre said it could take up to three hours before the waves reached the islands in its path.
New Caledonia, Tuvalu and Kosrae were also under threat, the centre said.
The Solomon Island town of Kirakira, on the island of Makira, was due to be the first affected if a wave has been generated, with an estimated time of arrival of 6.07pm (GMT).
Slightly more powerful quakes in the islands in 2007 and 2013 killed 52 and nine people respectively.
JUST IN: Tsunami watch issued for Hawaii following 8.0-magnitude earthquake in Solomon Islands. pic.twitter.com/xrXxAv4pDW
— ABC News (@ABC) December 8, 2016