Biometrics experts, San Jose State University National Biometric Test Centre director Dr Jim Wayman and Dr Tony Mansfield of the UK National Physics Laboratory, who had been evaluating the system based on its first eight months of operation, said the technology had performed remarkably well.
However, Wayman today conceded that "it's not yet clear that [the system will offer] any cost return yet".
The Australian government is estimated to have spent around AU$1.9 million developing and maintaining the system as a faster alternative to manual verification as Customs prepares to deal with sharp spikes in passenger arrivals expected as large-capacity aircraft such as the A300 start to enter service.
Current data based on the 84,000 transactions SmartGate has processed so far suggests it could improve on manual verification times by up to 65 percent on average.
SmartGate removes the need for manual staff checks by mechanically scanning each passenger's face for comparison with a mathematical representation of their facial features pre-stored on their passport. However, so far, the passport verification system has only been made available to Qantas long-haul aircrews that participated in initial testing of the system.
Wayman said that unless SmartGate was offered to a larger population of travellers it was unlikely to achieve the economies of scale required to justify its expense.
Adding to customs difficulties in achieving that scale, Wayman suggested that most Australians don't travel frequently enough to justify making enrolment for SmartGate available to the general public. According to information obtained by Wayman most Australians don't leave the country more than once every 10 years and, in any case, most spikes in passenger loads were expected to be caused by tourists.
"It may not be cost effective to enrol travellers who will only use the system once in a 10 year period," he said.
At the very least said Wayman, SmartGate should be rolled-out at other international airports and the eligible group widened to crews from all airline companies.
"I think you could justify the case if you were doing all air crew on a voluntary basis; you'd get enough passports through the systems to say yes it's paying for itself," said Wayman.
In addition, said Wayman, Customs might consider allowing aircrews to use the system off-duty and offer it to members of frequent flyer groups.