They state its not a surveillance system however by scanning someones face and using recognition software to identify the person coming through a check point I would argue that this is some kind of surveillance.
They actually contradict themselves on a couple of pages:
While SmartGate cannot determine someone's identity, it can verify that a person presenting a passport is the owner of that passport, to a high degree of certainty
http://www.customs.gov.au/site/page.cfm?u=4421
with this
what is smartgate?
SmartGate is a secure and simple system that verifies a person's identity, using face- recognition technology. Used at the Customs control point in an Australian international airport, SmartGate compares a traveller's face with their stored image when they present their passport. If there is a successful match, immigration and customs checks are made by computer to ensure that the border crossing is legitimate.
http://www.customs.gov.au/site/page.cfm?u=4243