More than 200 people have been rescued from the sea off Papua New Guinea (PNG)'s north coast after a ferry sank with up to 350 on board, officials say.
Captain Nurur Rahman, from PNG's National Maritime Safety Authority (NMSA), told the BBC most people had been rescued from the water.
Efforts were continuing to pick up as many as possible before sunset, he said.
Australia PM Julia Gillard earlier said the incident was a "major tragedy".
Ms Gillard said the authorities were urgently trying to find out if any Australians were on board.
PNG Prime Minister Peter O'Neill said the cause had yet to be confirmed, and he sent his sympathies to the families of those involved.
The MV Rabaul Queen, operated by PNG company Star Ships, was travelling between the towns of Kimbe and Lae.
It sent out a distress signal in the early hours of Thursday.
The Australian Maritime Safety Authority, which is assisting the PNG authorities, has confirmed that the vessel sank approximately 16km (9.9 miles) off Finschhafen.
Eight ships and three helicopters are at the scene helping with the rescue. Three Australian fixed-wing aircraft have also been sent, says the BBC's Duncan Kennedy in Sydney.
Earlier, Capt Rahman told the BBC he had reports of people floating in life jackets where the boat sank.
A Star Ships spokesman told the AFP news agency that "bad weather" was believed to have sunk the ship.
"[There are] survivors. At the moment rescuers from Australia are at the site. No fatalities have been reported yet," the spokesman said.
Star Ships is one of PNG's biggest ship operators.
bbc.com