The Rudd government has outlayed more than $1 billion to boost border protection as it continues to deal with a flood of asylum seekers heading for Australia.
The budget papers also show the cost of housing asylum seekers at Christmas Island has blown out to close to $1 billion.
More than $790 million has been allocated over the next four years in offshore detention measures, including $358 million in 2010/11 alone.
However, the budget papers show the number of arrivals is expected to decline with just $156 million for offshore management in 2011/12.
The cost of housing asylum seekers at Christmas Island this financial year has also been revised up, to $183.3 million, taking the total over the five years to 2013/14 to more than $973.6 million.
Close to $120 million has also been allocated over four years for the improvement of facilities, infrastructure and services on Christmas Island.
Onshore management costs have also increased, with the re-opening of detention facilities at Curtin Airbase in Western Australia, and the refurbishment of other detention centres on the mainland, expected to cost $143.8 million.
