“HMAS Warramunga rescued 76 people from the water and HMAS Albany rescued 68 people from the water. Tragically, four deceased persons were recovered,” Customs said in a statement.
“It is believed that there were approximately 150 people on board based on an assessment of information provided by the vessel’s crew. This number has been revised downwards from an initial estimate of up to 180 people,” the statement added.
A military plane managed to drop life rafts to those stranded in the water, many of whom were reportedly not wearing life-vests.
Customs said it suspended its search at 9.38pm (1138 GMT), with no further sign of survivors.
The Australian Maritime Safety Authority said it had been “in contact with the vessel most of the day” and rough seas had prevented sailors from boarding the ship to investigate the cause of its difficulties before it went down, 70 nautical miles from the remote Christmas Island outpost.
Hundreds of asylum-seekers have drowned on the dangerous sea voyage to Australia in recent years when their flimsy and overloaded boats sank.
The most recent accident, involving a vessel carrying 97 asylum-seekers over the weekend, claimed the life of a baby boy. Eight others were missing presumed dead when the search was called off on Sunday.
More than 13,000 asylum-seekers have arrived in Australia by boat since January 1, piling pressure on the ruling Labor party in an election year.