The Independent Police Conduct Authority has criticised police for chasing a fleeing driver at speeds of up to 167km/h before the man died in a crash.
Luke Yates failed to stop for a breath test near Taipa in Northland. The 22-year-old was chased by two officers for 2.3km and killed when his car hit a power pole on a country road.
Mr Yates was on his way to a cousin's 21st when he arrived at a compulsory breath test checkpoint near Taipa in April last year.
Toxicology results showed he was just under the legal blood alcohol limit, but had smoked cannabis before driving. The warrant on his Honda had expired and he wasn't licensed to drive a manual car.
Instead of stopping, Mr Yates swerved around the officer waving him down and then took off up Oruru Road. He was well out of sight by the time police took off after him, and 10 minutes later was dead.
Police told the Independent Police Conduct Authority they did not identify Luke Yates as the driver of the Honda when they gave chase.
The first officer said she did not consider it a pursuit, because he had such a head start. For that reason, she did not follow police policy - she turned on her lights, but not her siren, and didn't tell police communications that a pursuit had begun.
The officer reached a speed of 167km/h when a large blue explosion lit up the night sky. Seconds later, she had to brake to avoid crashing into a concrete power pole lying on the road.
The officer following her arrived at the scene to find the patrol car entangled in live power lines and Mr Yates' crashed car nearby. He was dead at the wheel.
The IPCA found officers were justified in chasing Mr Yates. However, it says they did not fully comply with aspects of police policies relating to speed, ongoing risk assessment, communications and the option of abandoning the pursuit.
It said the risk to safety, including Mr Yates' safety, outweighed the immediate need to apprehend him.
Far North police say they have acted on IPCA's recommendations and have re-trained all the officers involved. Area commander Inspector Wendy Robilliard says the loss of a young life is deeply regretted.
"Police have worked with the two staff members involved and they've received remedial training in relation to fleeing driver policy and also conduct and management of police pursuits."
Mother disputes police evidence
Police told the IPCA that they could not identify Luke Yates or see his registration plates - and that it was a clear night with good driving visibility.
But Mr Yates' mother, Donna Yates, disputes some of the police's evidence in the authority's report, saying neighbours who live nearby the crash scene told her it was foggy and unsafe for fast driving and all they saw was a blue flash.
"And in the report it says the conditions were clear. We have to accept it - we're not happy with it - but that's the way it is."
Ms Yates believes her son panicked when he sped away from the checkpoint officer. She says her son wasn't drunk - he just didn't want another fine - and she will never understand why police took the risks they did that night.
The IPCA report found no evidence that the patrol car had rear-ended Luke Yates' car, as some family members claimed at the time.