Police say a 54-year-old man found with stab wounds has died following a serious incident in Christchurch this morning.
The man was located by police in a stopped vehicle in the Richmond Park area at around 12.30am.
Police Commissioner Mike Bush said a search warrant was executed on a St Martins property late yesterday.
He said police discovered a number of firearms at the address.
Police negotiators spoke with the man over several hours before approaching the vehicle at 3.40am, when they discovered the man was critically ill with apparent stab wounds.
There were no firearms in the vehicle, but a knife was found.
Police said immediate first aid was provided but the man died at the scene.
A high priority investigation is underway to determine whether the man posed a threat to the community or not.
"This will include further searches of Christchurch properties and interviews with family and associates," Mr Bush said.
There is no evidence that this person had any involvement in the attacks of 15 March, however, this forms an important part of the investigation, he added.
As scene examinations continue, police will be present in the Richmond Park and St Martins areas.
"Members of the public who heard what they thought were explosions were hearing police deploying gas at the scene," Mr Bush said.
Earlier, a resident said he heard a gunshot after armed police stormed his suburban street.
Jeffrey Chisholm said he woke to a helicopter flying low over his Poulton Ave home about 3.30am.
He went outside to find his front fence had been broken and armed police running down the road.
"About quarter of an hour later I got a phone call from the police telling me not to go outside, that was about 4.30am.
"Then I heard a shot about 4.45am then I had another phone call at 5am saying 'you're allowed to go outside if you want to, you're all clear'."
Shirley Boys' High School principal John Laurenson also said part of North Parade was cordoned off when he walked to work along Marshland Road early this morning.
" wandered out to the quad and happily waved at them when they shined the searchlight on me, and thought 'oh this is quite exciting for an old feller like me'."
It was unnerving having a searchlight shone on him, he said, but he didn't think much of it.
He said he had since heard from police that the incident had been resolved.
"It's all cleared now, the police have been in and said that - I'm reading between the lines - [it was] a domestic incident.
"It's open for business, or we are open for business, now."
Christchurch Transportation Centre said North Parade was closed for a time overnight but had since reopened.
The public is urged to alert police on 111 of any suspicious activity.