|The boat crashed near Christmas Island where an Australian refugee detention centre is located [AFP]
Search and rescue operations are continuing for the second day after at least 30 people were killed when a boat carrying asylum seekers crashed into rocks at Christmas Island.
Julia Gillard, the Australian prime minister, said on Thursday that the passengers included people of Iraqi, Iranian and Kurdish origin.
"Yesterday we saw a truly horrific event, a terrible human tragedy on what is a very dangerous coastline at Christmas Island," Gillard said.
"I know the nation is shocked by what we have seen."
Navy and customs officers on the island rescued 44 people, including 11 children, after the vessel was battered to pieces on limestone rocks. But dozens of others were missing, and Chris Bowen, the immigration minister said up to 100 people may have been aboard, though the true number may never be known.
Gillard said search efforts would continue.
"We do not know with any certainy how many people there were on the boat so we've got to prepare ourselves for the possibility that more bodies will be found and that there has been futher loss of life than we know now,'' she told reporters.
Sea conditions were dangerous, with a cyclone hovering northwest of the island, which is the 135sqkm tip of a dormant volcano poking out of the Indian Ocean 2,600km from the Australian mainland.
"This is a very fluid situation and it's being conducted in what are quite difficult circumstances," Andrew Colvin, the Australian federal police deputy commissioner, said.
A local hospital treated more than two dozen injured, and authorities transported two women with the worst injuries to Perth in mainland Australia for treatment.
A victim identification team was due to arrive on Thursday.
The Royal Flying Doctor Service sent doctors to the island to treat the injured, Joeley Pettit-Scott, a spokeswoman, said.
Blunt forcce trauma was common among the victims, many of whom were battered by debris as they clung desperately to the remains of the sinking boat.
Christmas Island, located south of Indonesia, is a regular destination for boats carrying asylum seekers and is home to Australia's main offshore immigration detention centre.
In recent years, many asylum seekers have come from Sri Lanka, Afghanistan, Iran and Iraq. Generally, they first fly to Indonesia and then continue on to Australia in barely seaworthy boats.