In Solomon Islands, emergency crews are on their way to the remote Santa Cruz islands after a tsunami caused serious damage to at least three villages.
The one metre high tsunami was triggered by a 8.0 magnitude earthquake and travelled half a kilometre inland.
Police say at least six people have died and three others have been injured.
World Vision estimates five villages and 100 homes have been destroyed, but the full extent of the damage is yet to be assessed with debris and high water levels cutting off access to some areas.
Police spokesman Godfrey Abia has told Radio Australia it's still unclear how many people have been affected but that temporary accommodation is being provided for some of those who need it.
"Our officers down there have already set up some temporary shelter and campsites further up into the jungle and on higher ground," he said.
"They are organising and distributing food and water for the people at the moment."
The quake struck near the Santa Cruz islands, about 300 kilometres east of the Solomons, the Hawaii-based Pacific Tsunami Warning Centre said.
A 90-centimetre tsunami hit Lata in remote Temotu province, said the centre, which later cancelled warnings for other South Pacific islands, as well as for Australia and New Zealand.
An 11-centimetre wave hit Vanuatu, while a tsunami of around 50 centimetres reportedly hit New Caledonia. A small wave also hit Japan and Papua New Guinea. The Manus Island detention centre was evacuated as a precaution.
The US Geological Survey recorded more than 20 quakes near the Santa Cruz Islands, some registering 6.6 and 6.4.