Cracking down on the number of people arriving in Australia by air and then seeking asylum "wouldn't be worth the effort", senators have been told.
The boss of the Department of Home Affairs, which oversees the agencies managing Australia's border security, said stronger air travel checks on potential arrivals would be too onerous.
Secretary Michael Pezzullo said only 0.23 per cent of people who came to Australia by air between 2014-15 and 2018-19 claimed asylum.
He said there had been 40 million arrivals during the period, with more than 92,000 claiming asylum.
Mr Pezzullo said there would be "marginal gain" in putting more onerous restrictions on tourists and students.
"The pain wouldn't be worth the effort," he told a Senate estimates committee on Monday.
"It's a very controlled process. The additional effort to try and get that number down to zero ... is a vanishing return."
The home affairs head also boasted other countries were envious of Australia's track record.
"Frankly the reaction we get is the Meg Ryan reaction: 'We'll have what they're having'," Mr Pezzullo said.
But Labor's home affairs spokeswoman Kristina Keneally questioned this, pointing to a June report from the US State Department reviewing Australia's border screening processes.
"(Australia) did not convict any traffickers, initiated fewer prosecutions, did not adequately screen for indicators of trafficking among vulnerable groups and limited some victims' access to services based on their participation in law enforcement investigations," the report said.
Australian Associated Press