Photo: RNZ / Alexander Robertson
Police use of number-plate spotting systems has skyrocketed to nearly 700,000 times a year - or almost 2000 times every day.
Two years ago, the systems were used a third of that amount.
Legal challenges that this constitutes mass surveillance were recently thrown out.
When those challenges began, usage was just 500 times a day.
But a newly-released audit says 8600 police officers are using it, up by more than 2000.
The police officers tap into systems run by two private companies, mostly to check on 'suspicious' persons, and also used to investigate high-volume crime like at shops, gangs, wanted or missing persons and for "intelligence gathering", the audit said.
It noted the big rise, but did not offer an explanation.
The new audit, along with an inaugural review carried two years ago, essentially give police the approval to carry on.
The systems let officers call up CCTV footage of any car stretching back up to 60 days, by automatically identifying its number plate.
Both systems can access live or stored camera footage, often from store carparks or fuel station forecourts, running it through their customised Automated Number Plate Recognition (ANPR) technology. Mostly officers look at stored footage.
The Public Defence Service said two years ago that the use presented "a real risk of going into the territory of mass surveillance".
Usage has particularly shot up at one of two companies SaferCities, almost doubling from 250,000 searches to 450,000 last year.
Police helped SaferCities build its system in 2014.
Its VGrid technology can allow members of the public to send police still photos or CCTV footage.
Police have had a contract with the second operator Auror since 2015. Use at Auror rose from 195,000 to 250,000 searches last year.
Auror has become a half-billion dollar business in several countries, and frequently markets itself as a partner with police.
Police headquarters only did its first "baseline" audit on ANPR use in 2022, sparked by their admission they misused the system twice to track cars during Covid - when they reported the cars as stolen when they were not, to circumvent the rules on live tracking.
The audits noted how extra controls to catch misuse were added.
The Criminal Bar Association had said "we need to have a public conversation about the appropriate level of state surveillance in a free and democratic country".
But two judges last year ruled ANPR did not constitute a search that required that police need any sort of warrant.
This was in criminal cases where its use by police in evidence helped identify people subsequently convicted.
The technology also allows police to "track" a vehicle in real-time, but since the misuse detected in 2022 and a tightening-up, tracking has dropped to just 20-30 times a month.
Earlier, use of tracking jumped by six times between 2019 and 2021, to 2000 uses a year. The inaugural audit came shortly after.
"ANPR is a critical tool which can help achieve police's outcomes," the new audit said.
"Both vendors' systems have in-built controls and auditing capability, but until an October 2022 audit the efficacy of these controls had not been put to the test by police.
"While a small number of anomalies were detected (yielding a rate of apparent potential misuse in the order of 1 in every 1000 users), the baseline audit gave general reassurance that the two systems are being used as intended by those in police entrusted to do so."
RNZ asked SaferCities chief executive Scott Bain why police searches had almost doubled in a year. He said it was "appropriate that only police comment on the number of searches conducted on vGRID".
"Our system remains safe and compliant in terms of access and use. We take this responsibility extremely seriously and have checks and balances in place to provide those assurances."
The number of cameras linked to the two networks is not known exactly, but it is many thousands of cameras.
Even the courts, when they sought this information last year, concluded: "Auror does not hold information on the number of cameras contributing to the platform and declined to provide a list of all customers and locations on the basis of commercial sensitivity. The Crown accepts that the use of Aura is 'pervasive'."
A separate audit of officers' use of Auror specifically is due to report back in April.
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