Disaster authorities in the autonomous Papua New Guinea region of Bougainville are still searching for two people three days after their boat sank 30 kilometres off the Carteret islands.
Seven others from the same boat, including a mother and her baby, swam for two days with the help of four wooden pallets that had been in the bottom of the boat.
The director of Bougainville's Disaster Management Office, Franklin Lacey, says the group were all teachers on the Carterets who had been to Buka 86 kilometres away on school business.
Mr Lacey says some of the survivors are understood to need urgent medical care.
He has requested help from the United States Navy hospital ship, USNS Mercy, which is in Arawa on an aid mission.
"Some of them are still recuperating from the two nights swimming in the sea they still need to be checked up by proper medical people here. We haven't heard any answers yet from the American doctors who are here."
Mr Lacey says he believes some of the teachers were intoxicated when they left Buka in a three metre swell after ignoring a warning not to go to sea.
Three vessels are still looking for the two people still missing.