Senior frontbencher Tony Abbott has blamed Prime Minister Kevin Rudd's border protection policies for the loss of life following the sinking of a suspected asylum-seeker boat off the Cocos Islands.
At least one person had died while another 11 remained missing, feared drowned, after a boat carrying 39 suspected asylum-seekers sank 350 nautical miles north-west of the Cocos Islands on Sunday.
Two bodies were sighted in the water on Tuesday.
Two children, aged 13 and 14 are believed to be among the 11 suspected asylum seekers missing for more than two days. Hopes of finding them alive have all but faded with at least one person confirmed dead.
Australia has called off an air and sea search for survivors on Wednesday.
Home Minister Brendan O'Connor said there was no hope of finding anyone else alive after the boat carrying 39 went down in stormy conditions overnight Sunday, sparking frantic rescue efforts by passing ships and Australian planes.
"Medical advice received indicates that there is no further chance of survivability," O'Connor said in a statement. "This is a tragic incident."
Twenty-seven survivors have since been taken aboard the commercial ship the LNG Pioneer and will be taken to Christmas Island to be processed.
Asylum-seekers have returned as a major political issue in Australia this year after a sharp rise in arrivals, with critics blaming Rudd's softening of the tough policies of his conservative predecessor, John Howard.
Mr Abbott said the sinking of the boat and the stand-off between authorities and 78 asylum-seekers on an Australian Customs vessel in Indonesian waters showed the Federal Government's border protection regime had failed.
"You look at this terrible tragedy that's unfolding in the Indian Ocean at the moment and you've got to say this is a comprehensive failure and it's all the Prime Minister's fault," Mr Abbott told Fairfax Radio.
Mr Rudd maintained his border protection policy was tough but humane.
But Mr Abbott said the dismantling of the Howard government's border protection policies had prompted the surge in people-smuggling activity.
"What's so moral about policies which encourage people to take to the sea in leaky boats and give us the kind of tragedy that seems to be unfolding now in the Indian Ocean?"
