Up to five asylum seekers are believed to have drowned after a boat carrying more than 100 people sank north of Christmas Island.
Australian authorities called off search and rescue operations on Tuesday night after rescuing 106 people, Customs and Border Protection says.
"The suspension follows confirmation from on-scene crews and interviews with survivors that all survivors have been recovered," Customs said in a statement.
Information from survivors suggested that up to five people remained unaccounted for, but they may have gone down with the boat.
After an extensive search for survivors and bodies, none were sighted.
"It is therefore believed any people unaccounted for have gone down with part of the vessel," Customs said.
The 106 survivors are being transferred to Christmas Island for health and security checks.
They will all eventually be sent to Papua New Guinea or Nauru and could be resettled in those nations if found to be genuine refugees.
Meanwhile, federal Labor's hardline resettlement plan is facing its first legal challenge.
Sydney lawyer Adrian Joel, who represents a would-be refugee on PNG's Manus Island, lodged a challenge in the Federal Court on Monday. It's believed the case will eventually be heard by the High Court.
Mr Joel is expected to argue that PNG is not a suitable destination for asylum seekers.
Prime Minister Kevin Rudd dismissed suggestions the policy may go the same way as the Gillard government's Malaysia people swap deal, which was struck out by the High Court in 2011.
"We have exactly the right policy message on this and exactly the right administration to back it up," Mr Rudd told reporters in Brisbane.
The latest boat tragedy comes as Immigration Minister Tony Burke and Foreign Minister Bob Carr attended a regional anti-people smuggling conference in Indonesia on Tuesday.
Opposition Leader Tony Abbott warned against Senator Carr and Mr Burke signing up to any agreement that may come from the talks due to the fact that the government was in "caretaker mode" ahead of the election next month.
A legal challenge being mounted by PNG's opposition against the asylum seeker plan also picked up steam on Tuesday, with lawyers applying to add Manus detainee and asylum seeker Rawed Reza to the list of challengers to the controversial scheme.
