Five police staff are being investigated by an internal integrity group for misusing software that recognises vehicle number plates.

An audit found two of them used the system to track their own cars.

About 6000 staff can search third-party CCTV for previously captured footage of vehicles, while about 1000 can also track them in real time.

Police say the review of 350,000 searches shows overall staff are using the systems as intended.

It found 120 people looked up their own vehicles, but the police had not investigated if they broke the rules.

Police say they are tightening up controls to better prevent misuse and errors.

In response to increased used of the ANPR software, police brought forward a planned audit into the use of the provider platforms.

Assistant Commissioner Mike Johnson says this audit is an important part of ensuring all staff are adhering to guidelines and policy around the use of ANPR.

"It involved examining and cross referencing over 350,000 ANPR reviews from 2018 to 2022, which has built a full picture of ANPR data accessed by Police. The audit has confirmed that the vast majority of Police are using this tool within Police guidelines and can be trusted to use ANPR data responsibly.

"Of the many reviews audited only a small number of cases involving five Police staff warranted referrals to the Integrity and Conduct Group for follow-up."

Mike says it's disappointing to see that on a small number of occasions staff had not used the technology correctly, but overwhelmingly the review has shown how dedicated our staff are to using ANPR to help make our communities safer.

"It also showed that there is considerable overlap in the reviews between the two platforms used by Police, as they are providing the same service with access to different cameras, which has contributed to the increase in the number of reviews.

"Opportunities to better prevent misuse and errors, as well as making it easier to detect if action outside of Police policy happens in the future, were also key findings from the audit.

"Progress is already being made with both platform providers on ways to strengthen these controls.

"This has involved consulting with the Office of the Privacy Commissioner and the Police Association about the audit and its recommendations."

Mike says this is audit is an important first step in our work to safeguard the use of this technology.

Moving forward, he says regular auditing of staff use of ANPR platforms will be included into police's programme of internal audit and assurance work to provide continued reassurance about the use of ANPR provider platforms.

-Additional reporting by RNZ.