Police want to be able to use smart-phones to access driver licence photographs on the roadside, to stop people they pull over without identification from using false names.
But Police Minister Anne Tolley says it would breach privacy rules.
The debate has started in the wake of a court case involving Waldo Van Niekerk, pulled over in 2007 and 2009 for speeding and drink-driving. He did not have identification and claimed to be someone else. He appeared in court twice under the false name, was convicted, paid fines and was caught out only when the man he claimed to be was himself stopped for drink-driving.
Smart-phones and iPads are to be rolled out to officers next year and Police Association president Greg O'Connor said they should have access to the driver licensing database. The move would not give police access to anything they weren't already entitled to.
"Theoretically, police already have access to driver's licence photographs because, by law, you have to carry it when driving.
Logic dictates police should have access through electronic means as well," he said.
"There's no point having this technology if you can't access photographs. It's incredibly frustrating," he said.
But Tolley said such a move would require going back to every driver in New Zealand to ask them to explicitly agree to waive their rights under the Privacy Act.
"It's a serious privacy issue and it would be an enormous step for New Zealanders to take. It would be almost moving towards a police state."
Privacy expert and barrister John Edwards said police access to driver's licence photographs would be "controversial" considering the recent privacy breaches in the public sector.
"The licence is there to demonstrate your authority to drive a vehicle on New Zealand roads. It shouldn't migrate into being a de-facto national ID card. We are in a time of declining trust of the Government's ability to respect the private data that they hold."
Meanwhile, Van Niekerk was sentenced this week on two counts of perverting the course of justice by giving false details to police.
Judge Lawrence Hinton sentenced Van Niekerk to 300 hours' community work and six months' community detention. He was convicted and discharged for the original drink-driving and speeding offences, which he pleaded guilty to earlier when appearing under the name Theo De Villiers.
The judge said Van Niekerk's offer to pay De Villiers $3000 for emotional harm had "tipped the balance" from home detention to the lesser punishment of community detention.
De Villiers said $3000 would only just cover his legal bills.