The federal opposition is accusing the government of losing control of Australia's borders, with the cost of managing asylum seekers blowing out by more than $3 billion.
Tuesday's federal budget showed asylum seeker costs would be almost $2.9 billion in 2013/14 - more than $1.5 billion more than previously estimated.
Over the four years to 2015/16, the blowout totals $3.2 billion.
Opposition immigration spokesman Scott Morrison says the budget still falls well short of what the likely costs will be if the government's "failed border polices" continue.
Labor's claim their asylum budget costs will fall by 50 per cent over the forward estimates to less than $1.5 billion is "absurd", he says.
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"If Labor was preparing their budget on the basis of a change of government, then it may make some sense," Mr Morrison said in a statement on Wednesday.
"But their budget must be based on their policies, and under their failed border policies, the boats will keep coming and the costs will keep rising."
Prime Minister Julia Gillard earlier said the government was looking at reviewing Australia's refugee status determination process, suggesting less asylum seekers may have their applications approved.
This could see Australia's acceptance rates "converge to the international norms", she said.
"It will send a message of course about how many people's claims are accepted," Ms Gillard told Sky News.
The review would look at how the refugee review tribunal assesses claims, the prime minister said.
Mr Morrison said the government's asylum seeker budget blowout since it came to office was now $10 billion.
Under Labor the number of boat arrivals has increased from two people per month in 2007/8 to more than 2000 per month this year, Mr Morrison said.
