A parliamentary committee in Canberra was told on Monday that asylum seeker boat arrivals in Australia could total 30,000 in 2013.
"At the current rate of arrivals, we could see upwards of 25,000 to 30,000 people coming (in 2013)," said refugee advocate Paris Aristotle.
"There is simply no way our navy has the capacity to get to every boat that will get into distress in those circumstances."
AAP reports Mr Aristotle was part of a panel which made 22 recommendations in August to the federal government on asylum seeker policy.
The Gillard government adopted all of the recommendations which included the reopening of offshore processing centres on Nauru and Manus Island.
Mr Aristotle said a long-term commitment was needed to stop the boats.
"If we think this is going to be fixed in three months we are delusional," he said.
Panel chair Angus Houston told the committee that since August at least 213 people had died at sea and more deaths were likely in coming months.
"With the monsoon season upon us now I think it's inevitable there will be further loss of life at sea," he said.
AAP reports that since August, Australia has returned more than 700 Sri Lankans who arrived by boat, to their homeland after deciding they were not refugees.
Mr Bowen said this was discouraging others from making the journey to Australia.
"We've seen a very big reduction in the number of people arriving from Sri Lanka in recent weeks - it's been 13 days or so since we had a boat from Sri Lanka," he told Fairfax Radio on Monday.
The federal government announced on Monday that it has reopened the Pontville immigration detention centre in Tasmania and 95 Afghan men had been transferred there from Christmas Island.
The centre has a capacity of 400 and is expected to receive more detainees.