The airline has not provided information about the age or nationality of the man.
Those who were on board the Boeing 737 aircraft to Air Niugini were picked up by locals in small boats from the plane that lay halfway underwater. Of the seven injured, only one of them had serious injuries.
“It was pure luck that nobody lost life,” said Glenn Harris, security inspector in the Micronesia Federation.
The plane, which came from the island of Pohnpei, landed in the water before it reached the runway. It is not yet clear whether the captain notified the airline leaders or whether there were technical problems behind the buklanding.
Air Niugini is the national airline of Papua New Guinea. It flies to a number of destinations in Australia, Southeast Asia and the Pacific.