A gun club that helped hone the capabilities of a disabled gunman shot dead by police says it could not have foreseen such a tragic event.

Wheelchair-bound Shayne Richard Sime, 42, was killed by members of the armed offenders squad at his Christchurch home on Sunday night after firing more than 100 rounds, wounding an AOS member and a neighbour, and damaging homes in the area that had to be evacuated.

The injured AOS member has had surgery to remove shotgun pellets from his face and the neighbour is in a stable condition after being sprayed with pellets from his shoulder to his groin and being forced to run for his life.

"What we do know is that the police officer was shot, the AOS members returned fire and Mr Sime was found dead after the AOS squad members entered the house," said Detective Superintendent Brett Kane.

The shooting comes after Napier gunman Jan Molenaar shot three police officers, killing one, and a civilian last month.

The police officers' union says it is fortunate the AOS could be called on to confront Sime, but it is now time for a serious debate about whether police patrolling the streets should be armed.

"It's time that we didn't steadfastly say 'absolutely not', which is what we are hearing currently, unfortunately, from the [Police] Commissioner," said Police Association president Greg O'Connor.

"Surely it's time we started to understand just how dangerous an environment we are working in here."

Sime was known to police and believed to be in a suicidal state. He had been a licensed firearms holder since 2006. Police said he was a paraplegic who also suffered from a head injury, while some who knew him say he had muscular dystrophy.

The shootings have come as a shock to the New Zealand Handloaders Association gun club, where Sime had been a member for about six months.

"I don't think anyone I am aware of at the club would have predicted anything like this," said club secretary Graeme Barber. "There would be nothing that I saw of him that would indicate anything like this. He was just like anyone else - he liked guns and talked about it."

Police were called to Sime's house in February after a neighbour reported hearing shots. Sime was found to be firing his son's BB gun at a cardboard box and was not charged.

Mr Barber said Sime would come out to the club on Tuesday evenings to fire shotguns at clay targets. He was "affable and friendly and pleasant".

"He enjoyed his shooting. He was safe with firearms but he also needed a little bit of help to use them because of his disability. But he was never unsafe or irresponsible."

Some have branded Sime a loner, but Mr Barber said: "He was never a problem. He would socialise with people, talk to people."

Sime had also been a member of Parafed Canterbury, which provides sport and recreation for disabled people, for some time and regularly used the specialised gymnasium.

Mr Kane said a shot was first fired by Sime in the cul-de-sac of Wadhurst Place, in the Christchurch suburb of Burnside, about 5pm on Sunday but this was not reported.

Resident Deborah Scott lives a couple of houses away from Sime and said the firing started more like 4.30pm. "We thought it was kids banging a tin fence."

She, her son and others went to see where it was coming from but couldn't see anyone who could have been making the noise. "We weren't told of anything until 9pm when our neighbour alerted us to the situation."

Police were called about 8pm and the area was cordoned off at 8.20pm. About 40 residents were evacuated.

Officers negotiated with Sime for two hours, during which time he fired indiscriminately.

"Shots were fired from the front and rear of the property, and Mr Sime showed some agility," Mr Kane said.

It is understood Sime had contacted his family, saying he was suicidal, and also made threats to police. Alcohol may have been involved.

Sime's 39-year-old neighbour was standing near his front door when "peppered with [shotgun] pellets from his shoulders through to his groin". He escaped over a rear fence and was yesterday in a stable condition.

The AOS member shot by Sime will make a full recovery.

It is understood Sime lived alone, but had a child living in Australia.

Residents will not be allowed back to their homes for a day or two.