A first-ever test of facial recognition on New Zealanders' faces has found no bias against Māori, but the technology still needed improving on one front, new results show.
The successful testing of the accuracy of the new online Identity Check tool - which locally matches selfies against official database photos - provides a buttress for Internal Affairs (DIA) as it aims for a much wider rollout of the system.
"There are no significant disparities in liveness and matching engine performance among the tested ethnic groups," said the 33-page test report by globally-accredited facial recognition (FR) tester Bixelab.
"Despite the physiological differences among the tested groups, reliable performance is observed across the tested participants of Māori, Non-Māori ('Others'), and Pasifika groups."
The rollout to date - mostly by the Ministry of Social Development since last November, initially relied on overseas tests that indicated the FR probably was not biased.
But FR does have a track record of being less accurate on people with darker skin tones - so DIA said it had to test at a local level.
Identity Check passed three types of test, but did show an issue when it came to what testers called "imposter" or non-mated comparisons.
"It's noted that there is scope for improvement on false accepts which did show slightly higher error rates for Māori and Pasifika," the report said.
"It is our recommendation that ongoing evaluations further enhance system capabilities and ensure public transparency, reaffirming the importance of fairness and equity for all users."
The minor variations did not impact users but "they suggest that any future adjustments to system configurations should be made cautiously to ensure continued equitable performance".
On the basis test of matching the selfies with driver's licence or passport pictures, the system returned some varied scores but not enough to matter.
"This did not impact on the system's ability to consistently match genuine users of varying ethnicities accurately."
The tests did not involve any Māori with Tā moko.
The system must also be able to verify a photo is a "live" shot and not some cardboard cutout or other fraud - called a "liveness" check.
It scored 87 percent success in liveness testing.
The system also matches one selfie against another at two points - called "liveness matching" - and only one of these failed.
"No statistically significant variance in liveness performance was observed between Māori and other participants, indicating consistent performance across these groups."
The tests were run on a representative sample of 146 volunteers.
DIA said that 75,000 people had so far used Identity Check successfully 94 percent of the time, to verify online who they were.
It envisaged rolling it out nationally, not just as an option for people to access dozens of public services, but also for the private sector, for things like setting up a bank account without leaving your couch.