The coroner has strongly criticised police in his ruling on the death of slain father Halatau Naitoko.

In his findings released this afternoon, Coroner Gordon Matenga said the Auckland man was killed by a shot fired by members of the Armed Offenders Squad (AOS), who were shooting at an armed man following a police chase.

Matenga ruled the death was accidental.

The incident happened on the north-western motorway in January 2009, after an hour-long police pursuit of Stephen McDonald in which shots were fired.

McDonald was later convicted and sentenced to 13 years after he admitted to 23 charges, including firing at police, possessing a firearm, aggravated robbery and unlawfully getting into a motor vehicle.

Naitoko died after being struck in the chest by a bullet intended for McDonald.

Family spokesperson Peter Sykes said Naitoko's family feared a similar tragic shooting could happen again, but also accepted there was little to avoid a similar "complex situation" arising.

"In some ways it's sad news, obviously there's nobody specific to blame. We have a grief industry which says we need to blame before we get over grief."

Sykes said the family were doing "amazingly well" and still ran their courier business.

"Part of the family's response is it doesn't matter what the [coroner] says, our job is to learn from it and continue Halatau's legacy."

Matenga said he was greatly concerned about the fact the officers had missed their intended target with four shots "from a reasonably close range of between 7 and 9 metres".

Combined with the failure of one officer, "to appreciate what was within the line of fire indicates to me a need for further training and an acknowledgement by AOS that experience matters".

The two officers were the least experienced of those to respond to the incident, he said.

"Whilst I accept that (unidentified officers) A81 and A84 were qualified having attended and passed all the relevant training provided by police they were still learning to apply their training in real life situations."

"No thought was given" to the experience of the members when they were paired, aside from readiness to deploy, he said.

"This was an active mobile shooter situation leading the police on a chase around the streets of Auckland.

"The uniqueness of the situation should have in my view given the senior AOS officer pause to consider the relative experience of his squad and separate into sections taking experience into account."

Police decided not to lay charges against the officer who fired the fatal shot.

Matenga also criticised one officer - part of the chasing group of officers, for stopping and exiting his vehicle when the chase came to an end, drawing his weapon and firing it in the direction of a fleeing McDonald.

"This was a gross infraction of the Police Instructions on Firearms, appears to have been incredibly dangerous and is a matter I will refer to the IPCA [Independent Police Conduct Authority] to deal with," he said.

Matenga said police had already made some changes in the wake of the shooting, but he recommended other measures including:

- Developing AOS training modules which more closely resembled real operations.

- That AOS commanders take into account the experience of its squad members and where possible pair inexperienced members with those more experienced.

- Buy video surveillance capability for the Eagle helicopter, to allow the northern communications centre to watch events in real time and allow them to better manage incidents.

Matenga said that while he was critical of the officer who fired the fatal shots and his "awareness of the situation", he said the actions of both officers who fired shots were justified.

He detailed the aggressive stance taken by McDonald, the fact he was armed and that he had fired the weapon to intimidate police.

Identified only as A84, the officer who fired three shots did so to protect bystanders and his colleague, Matenga said.

"But that is not the end of the matter. I am looking for ways to ensure that an accidental shooting of this nature does not happen again or (to) at least reduce the chances of a similar occurrence in the future."

Police "deeply and sincerely regret" the accidental shooting of Naitoko, assistant commissioner Allan Boreham said after the coroner's findings were released.

He said it was right that police power to use firearms be publicly scrutinised.

Boreham said the case was a difficult situation to manage on a number of levels.

"Police were dealing with an armed, mobile, unpredictable, drug fuelled offender who had threatened several members of the public and police with a firearm and had further shot at police officers and at the police Eagle helicopter.

"There was a very real threat to public safety.

"The police officers put themselves in the line of fire to stop Stephen McDonald."

Boreham said the officers who were involved in the capture of Stephen McDonald acted with courage and determination but were devastated by Naitoko's death.

The chair of the IPCA, Justice Lowell Goddard, said the IPCA investigation into the shooting was finished and it was preparing its report for release.