If Sri Lanka and the United States can intercept boats carrying asylum seekers then so can Australia, the Opposition immigration spokesman Scott Morrison said.
"Sri Lanka is stopping boats leaving their shores, the United States coast guard is stopping boats coming to their shores," he told Fairfax Radio Network on Tuesday.
"The United States coast guard so far this year has turned back 2431 people on boats.
"This policy can be done and the suggestion by the government that it can't is more a comment on their lack of resolve."
In the past few days, Sri Lankan authorities have arrested more than 170 suspected asylum seekers trying to get to Australia by boat.
Australia's opposition migration spokesman said the Australian navy is well used to boarding vessels, including those belonging to smugglers, in dangerous circumstances elsewhere.
"And our government is saying our navy can't turn back a fishing boat - it's an insult to the navy," he said.
The Australian opposition has agreed to hold talks with an expert panel set up by the federal government to devise a politically acceptable policy on asylum seekers.
But it has knocked back Prime Minister Julia Gillard's invitation to take part in a multi-party committee looking at ways to resolve a parliamentary impasse on the issue.