Tsunami could be higher than some Pacific islands
The International Federation of the Red Cross warned that the tsunami could be higher than some Pacific islands.
Spokesman Paul Conneally said: "The tsunami could get to between seven and 10 metres high, which is higher than the sea level of some Pacific region countries.
"It is certainly a significant threat and we are taking it very seriously.
"We have triggered all of our response mechanisms in the Pacific region. Our main concern now is to get people out of harm's way."
People are being evacuated from coastal areas in countries including Russia and the Philippines with the assistance of the Red Cross, Mr Conneally said.
He added: "We have to be prepared for different scenarios, including the worst-case scenario, and our volunteers are mobilised."
The Philippines, Papua New Guinea and the Pacific islands in general are thought to be facing the highest tsunami risk, he said.