Police behaved reasonably and appropriately in dealing with a Christchurch man who showed support for the mosque shootings and later took his own life, a coroner has found.

Coroner Heather McKenzie found Artemiy Dubovskiy - who was known as Troy - died by suicide early on 27 March 2019 following an hours-long stand-off with police.

Officers had raided the 54-year-old's house the day before, after he sent a threatening email to a school.

On 15 March 2019, a white supremacist terrorist fatally shot 51 people at two Christchurch mosques. Dubovskiy sent an email to a family member's former school five days later expressing support for the massacre, describing it as "heroic ideological self-sacrifice".

Dubovskiy was one of about 150 people of interest who came to police attention following the Christchurch terror attacks.

Police found a loaded semi-automatic rifle fitted with a suppressor and laser sight, a Luger pistol, a substantial quantity of ammunition, a tactical vest, a taser, knives, a baton and assorted Nazi clothing and paraphernalia when they raided Dubovskiy's St Martins home on 26 March 2019.

In findings released Wednesday, Coroner McKenzie said Dubovskiy served with the Russian military in Afghanistan, Africa and Chechnya before moving to New Zealand.

He worked as a welder and machinist in New Zealand before being injured in the 2011 Christchurch earthquake.

He was on a sickness benefit at the time of the terror attack.

Dubovskiy was known to police and had 21 previous convictions, including unlawfully carrying an imitation firearm, threatening behaviour, breaking and entering with a weapon, and assault.

He was not home during the March 2019 police raid.

Neighbours told police Dubovskiy had been recently spotted playing with weapons and an army kit in the early hours of the morning.

A search of another address linked to Dubovskiy found a replica rifle with white words painted on it similar to the firearms used by the terrorist responsible for the Christchurch mosque massacres.

Dubovskiy became aware police had searched his home.

Police feared he was a significant threat to officers and the public, so they began to search for Dubovskiy.

Shortly before midnight he sent a text message to someone saying: "I won't go to prison again. There's only one way ... goodbye."

Just after midnight his cellphone pinged near the Christchurch Central Police Station and the justice and emergency services precinct went into lockdown with guards deployed.

His car was spotted by a patrol officer soon after and he drove down a dead-end street in east Christchurch.

A police negotiator called Dubovskiy at 12.38am and negotiators remained in contact with him for about two-and-a-half hours.

During that time Dubovskiy also called family members on another phone.

Shortly before 2am he told his mother in Russian that he was not going to give up, to which she responded: "Well, that's ok then."

Just before 3am there were issues with his phone and police lost contact with him.

The negotiation team made 80 unanswered calls to Dubovskiy's two phones.

At 3.41am officers saw Dubovskiy slump in the seat of his vehicle after self-harming.

A minute later, under the cover of a NZ Defence Force light operational vehicle, officers moved forward and removed the critically injured Dubovskiy from his vehicle.

Emergency services, including paramedics, tried to provide medical care but Dubovskiy was declared dead at the scene at 4.32am.

Police had feared his vehicle might have contained an improvised explosive device but the Defence Force Explosive Ordnance Disposal Squadron confirmed there were no explosives in the car shortly before 5am.

Dubovskiy's family complained to the Independent Police Conduct Authority (IPCA).

The IPCA found police dealt with the situation lawfully and appropriately and did not find any misconduct by the officers involved or any breach of policy.

Coroner McKenzie also found police actions and inactions were appropriate during their dealings with Dubovskiy on 26 and 27 March 2019.

"First, I am satisfied that it was reasonable for police to form the view that Mr Dubovskiy presented a significant risk to the public," she said.

"Mr Dubovskiy presenting a significant risk was heightened upon execution of the search warrants on 26 March 2019. Given what was found, it became imperative for police to quickly find and contain Mr Dubovskiy. This assessment does not depend on the status of some weapons as being imitation or not completed."

Coroner McKenzie did not find any deficiencies in the search for Dubovskiy or negotiations with him.

"Fundamentally I find that throughout the negotiation, Mr Dubovskiy could have come out of his vehicle at any time, noting that he came out once and then retreated back inside. The negotiation had been going for approximatively two hours and 20 minutes before communication was lost. Even after communication was lost, Mr Dubovskiy could have signalled to police that he wanted to continue negotiating," she said.

Dubovskiy's family had raised the possibility police officers behaved differently than they would have otherwise because of trauma or a heightened response following the Christchurch terror attack.

"There is no evidence before me that police officers involved were traumatised by the mosque attacks and that this coloured their actions," Coroner McKenzie said.

"The police response was influenced by their intelligence on Mr Dubovskiy, including the email; the items found during the search warrant at addresses associated with him; his criminal record; Mr Dubovskiy's statements to police or on the phone to his mother; what he had said about his intention to attack police or the government; and how the negotiation was progressing.

"The mosque attacks were properly relevant context in the setting of established knowledge that copy-cat attacks can follow, of the heightened security atmosphere in Christchurch and of Mr Dubovskiy's support of the attacks. However, again there is not evidence that the actions of police attending on 26 and 27 March 2019 were influenced by trauma from the earlier attacks."

The coroner did not make any formal recommendations.