Australian Prime Minister Julia Gillard says about 90 people were aboard the boat carrying asylum-seekers that sank off Christmas Island last week.
Ms Gillard says about 18 people are believed to remain unaccounted for after the shipwreck, with 30 bodies having been recovered.
She says the death toll could be as high as 50, though the exact number of people aboard the wooden boat may never be known.
A search by police divers for bodies near the accident location has been suspended, the ABC reports.
Federal police are preparing to charge three Indonesian crewmen who were on the boat, but will not speculate about whether the men will be accused of manslaughter.
Ms Gillard says she is sticking to her strategy to disrupt people smugglers to prevent future tragedies.
"We do want to smash the people-smuggling business model," she says. "We want to take out of the hands of people smugglers the very evil product that they sell, and that is why we are working on a regional protection framework and regional processing centre."