Australian authorities have ordered an urgent review of security at Sydney's international airport after the theft of two mainframe computers from a restricted customs area.
The contents of the computers have been the subject of speculation
It is believed they were taken by two men posing as technicians at the end of August.
The federal government is investigating the security breach, but has denied media reports in Australia that the computers held thousands of confidential files.
The theft is an embarrassment for the authorities at Sydney Airport, the busiest in Australia.
The two suspected thieves told guards they were employees of the airport's computer department.
They were allowed to enter the customs division mainframe room, which is a high-security zone.
The men spent two hours disconnecting the computers, before calmly walking out, pushing the machines on trolleys.
The Customs Minister, Chris Ellison, has said there will be an investigation and that security will be tightened.
The government has insisted that no sensitive information was kept on the computers.
The Sydney Morning Herald newspaper had claimed that top security communications between customs investigators, the federal police and Australia's main domestic spy agency ASIO had been lost.
The chairman of a parliamentary enquiry into aviation security has demanded to know why his committee was not told of the theft that happened 10 days ago.
Customs officers who gave evidence earlier this week have been recalled.
One senior official told the committee she had not wanted to damage a police investigation into the robbery by making it public.