The Australian government is planning to allow 90% of travellers to pass through passport control without human help by 2020.
With a $100m (£80m) budget, it has begun the search for technology companies that could provide biometric systems, such as facial, iris and fingerprint recognition.
But University of Wollongong technology and biometric expert Prof Katina Michael told the Guardian newspaper that such technology could pose a risk to privacy.
"Even if the system works, is that ethical to impose this system on the entire populace without even asking them?" she said.
"I see the perceived benefit, but what I do know is that there will be real costs, human costs, not only through the loss of staff through automation, but also through discrimination of people who may appear different."