A tsunami generated by a powerful undersea earthquake off the Solomon Islands is reported to have killed five people, flattened three villages and damaged dozens of homes.

Local officials in the Solomons say two 1 and a half metre high waves hit the western side of Santa Cruz Island after the magnitude eight quake.

Charity workers on the islands say four coastal communities were most affected and Lata airport is closed.

The majority of the Lata population has moved to higher ground - with women, children, elderly and people with disabilities moving further up the mountains.

The Pacific Tsunami Warning Center says all other alerts in the region have been cancelled.