Police are looking to upgrade their surveillance gear to include "advanced facial recognition technology" able to be used through closed-circuit cameras.

With a network of CCTV cameras across the country, it would give criminals fewer places to hide. Also in the high-tech system would be suspects, prisoners, firearms licence details, missing people and those on the child sex offender register.

Police stressed in a response to an Official Information Act request that any decision on the software, which has gone out to tender, is far from a done deal.

JOHN KIRK-ANDERSON/STUFF It is hoped that police officers on the beat will be able to get photos from the new cameras sent directly to their phones.

They could not say how the new surveillance system would be an improvement on the old, but said their current facial recognition technology was "out-dated and limited", and clothing, scars, marks and tattoos could not be viewed other than in text or code.

READ MORE:

* Cambridge Analytica 'misuse' may affect nearly 64,000 Kiwis, Facebook says

* Facebook says sorry for Cambridge Analytica scandal with newspaper ads

* Sensors in the city - big brother is watching, listening and smelling

* Big Brother is watching your mobile

Police national forensics services manager Inspector John Walker said the new tecnology would allow "advanced facial recognition technology to assist in the identification of unknown offenders where a facial image is available for comparison – for example through CCTV".

CAMERON BURNELL/STUFF Human rights lawyer Michael Bott says New Zealand needs to talk about privacy.

There was an objective that officers on the beat would be able to get photos directly to their phones, where they could show witnesses a series of images.

Much of the technology was already covered by existing legislation, but Walker said some legal advice had been sought on privacy issues. He would not say what this involved as this was legally privileged.

Wellington human rights lawyer Michael Bott said the police move showed it was a time New Zealand had a debate about what information stayed private in this era of big data and surveillance.

The Cambridge Analytica case, which effectively dragged an "electronic driftnet" through people's data then used the gathered information to manipulate, showed how powerful big data was.

The State could effectively monitor mobile phones, CCTV, banking details, spending, where you go, what you buy, and your preferences.

While the tender documents showed a lot of "nice-to-haves", some of it could come at a cost to our privacy, Bott said.

"We want to have that debate before the nightmare happens."

In China, technology was able to identify a single person in a crowd of 60,000. While there was no suggestion New Zealand had technology at that level, we did need to move carefully to avoid an "Orwellian" future, he said.

"We are not yet a police state, but is it a debate we should be having?"

Police said they were able to access CCTV cameras run by local authorities or other groups that had put them in place for crime prevention. Some were monitored by police

"Access to those not monitored by police may be through the consent of the owner or if required, a search warrant or production order," a police statement said.

CCTV in commercial or private places could be handed over voluntarily or via a search warrant or production order.

Sharing of CCTV information was covered by the Privacy Act, which police had no plans to try to change.

A spokesman for the privacy commissioner said his office had not yet talked to police about the proposed use of biometric technology, but that was not unusual so early in the process.

"We look forward to having those discussions. We expect that police will be aware of their Privacy Act obligations and responsibilities when collecting personal information".

It was expected police would perform a privacy impact assessment on the proposed technology, the spokesman said.

If accepted, the technology would likely be in place in 2019, police said.