A powerful magnitude 8.0 earthquake and tsunami hit the Solomon islands on Monday, and people from Honiara to Australia fled for the safety of higher ground.

The shallow quake hit Gizo island, northwest of the Solomons capital Honiara, the hardest. It damaged shops, schools and a hospital on the low-lying waterfront, while the following tsunami wave sucked dozens of houses into the sea.

"There are a lot of people who are without shelter. We understand that a lot of villages in other areas of the Western Province and Choiseul Province were totally wiped out," Solomons National Disaster Council chairman Fred Fakari said on Tuesday.

Mr Fakari said disaster teams and international peacekeepers in the country had not yet reached the area and were hoping to arrive in Gizo on Tuesday by helicopter to begin a full damage assessment.

Western Province Premier Alex Lokopio said an estimated 4,000 people were sheltering in the hills amid warnings that quake aftershocks could generate more tsunami waves in coming days. Islanders were in desperate need of water, food and tents, he said.

Fakari said the death toll was still unknown, but initial estimates pointed to at least 20 dead and more still missing.

Government and Red Cross disaster teams are taking tents and supplies to the affected area. Australia, which said the wave also hit the western Papua New Guinea island of Bougainville, has offered US$1.6 million.

The United Nations said it had a full Disaster Assessment and Coordination (UNDAC) team on standby for deployment to the Solomons.

Reuters