SAN FRANCISCO: Tsunami warnings were issued Saturday for the entire US West Coast after a massive volcanic eruption across the Pacific Ocean in Tonga, with tsunami waves triggering low-level flooding in Hawaii.

The US National Weather Service issued tsunami advisories from the bottom of California to the tip of Alaska's Aleutian islands, predicting waves of up to two feet (60 centimetres), strong rip currents and coastal flooding.

"Move off the beach and out of harbors and marinas in these areas," it advised.

The Pacific Tsunami Warning Center said "a tsunami is currently being observed" in Hawaii, but said there was "no reported damage and only minor flooding throughout the islands."

Frightened Tongans fled to higher ground as the eruption triggered a tsunami in the island nation, with a four-foot wave observed in Tonga's capital Nuku'alofa.

Similar warnings were issued by nations throughout the Pacific, including New Zealand, Fiji, Vanuatu and Australia as well as for coastal Chile.

The latest eruption of Tonga's Hunga Tonga-Hunga Ha'apai volcano lasted at least eight minutes and sent plumes of gas, ash and smoke several kilometres into the air.

It came just a few hours after a separate Friday tsunami warning was lifted due to a previous eruption.