Rescuers scoured treacherous seas on Thursday for survivors of a refugee boat wreck that killed at least 28 people off Australia, renewing heated debate on the grim plight of boat people travelling from Asia.
The wooden craft, crowded with up to 100 Iraqi, Kurdish and Iranian asylum seekers and their children, hit rocks at remote Christmas Island on Wednesday and was shattered by huge waves as residents looked on helplessly.
Traumatised survivors pulled from the sea after the disaster huddled in a hospital and reception centre on Thursday, with the most seriously injured flown to Perth, amid dwindling hopes of finding their fellow passengers alive.
Prime Minister Julia Gillard said the harrowing search and rescue mission had resumed at first light but warned the death toll would rise as searchers struggled with brutal conditions.
"We do not know with any certainty how many people there were on the boat," said Gillard, who cut short her vacation to respond to the emergency.
"We have got to prepare ourselves for the likelihood that more bodies will be found and there has been further loss of life than we know now."
The prime minister said 42 survivors had been plucked from the ocean, downgrading an earlier estimate of 44, while 28 bodies had been recovered, also including a number of young people and children.
Immigration minister Chris Bowen earlier said there had been between 70 and 100 people on board the leaky fishing boat, according to survivors, adding that the exact number of dead would "probably never" be known.
Medics believe as many as 50 people may have perished on the jagged limestone outcrop.
"Yesterday we saw a truly horrific event, a terrible human tragedy on what is a very dangerous coastline at Christmas Island," said Gillard.
"I know the nation is shocked by what we have seen."
Cyclonic conditions whipped up by an approaching monsoonal storm were hampering search efforts, police warned, while the task of identifying victims had begun in a makeshift morgue on the island.
Gillard was forced to defend border police as questions mounted about how the boat managed to traverse the most closely-watched people smuggling corridor between Indonesia and Australia without being intercepted.
She said the boat had approached the island, some 2,600 kilometres from Australia's mainland, in the predawn darkness and "extreme weather conditions" meant it wasn't detected "until seen from Christmas Island itself".
"In very rough and dangerous seas there is a limit to what can be achieved through radar and other surveillance mechanisms," Gillard said, adding there would be a criminal investigation as well as a coroner's probe.
"What we know from past events like this one is that the facts take some time to compile," she said.
At least 5,000 asylum seekers from Iraq, Afghanistan and Sri Lanka have made their way to Australia this year, often on leaky boats from Indonesia.
Lawyers and refugee advocates including Amnesty and the UNHCR said the tragedy highlighted the desperate plight of refugees and urged greater cooperation between nations for more humane solutions.
Survivors of the wreck, including 11 children, were recovering Thursday in a hospital and a reception centre on Christmas Island, home to Australia's main immigration detention centre for boat people.
Two seriously injured women were flown to hospital in Perth, one with abdominal injuries and the other suffering respiratory problems from inhaling sea water and diesel, medics from the Flying Doctors said.
A further three critically ill people were to be flown to Perth on Thursday, Gillard said, with three more under watch in the island's hospital.
She said survivors would be dealt with on a "case-by-case basis", with some likely to be held in the community under a policy, announced in October, that removes children and families from immigration detention.
Locals told they were woken at dawn Wednesday by the screams of victims, and gathered life jackets and rushed to the cliffs to offer help. But they were helpless as strong winds blew the flotation devices back onshore.
The terrified group drifted for about an hour after losing engine power, and only one man managed an "incredible leap" to safety before the waves smashed the rickety vessel apart on the rocks, local shop owner Simon Prince said.
People were crushed against limestone as navy rescuers battled towering swells to reach them in inflatable dinghies.