Reports from the maritime rescue effort underway off Papua New Guinea's Morobe province after the sinking of the ferry, the MV Rabaul Queen, indicate that most of the estimated 300 passengers have survived.
The National Maritime Safety Authority says the ship sank about 16 kilometres off Finschhafen on PNG's north east coast while on its way from Kimbe on the island of New Britain to the mainland city of Lae.
It sent out a distress signal at about 5AM local time that was picked up by Australia's Maritime Safety Authority.
The NMSA is co-ordinating the rescue effort with help from six foreign merchant vessels that were in the vicinity which have been picking up survivors as well as National Disaster vessels.
Australia's search and rescue services are involved too.
The NMSA's Operations Manager Captain Nurur Rahman says their vessels dispatched to the accident zone confirm at least 193 people have been rescued while Australian rescue co-ordinators say the number is as high as 219.
"We don't know the exact location of the ship but we know the location from where the distress signal was sent out. That way we know and we also now know that people are swimming around that area, they are drifting."
Captain Nurur Rahman