A 38-year-old West Auckland man was shot about 6pm after police went to a property on Nikau Street in New Lynn to look for a man in connection with an alleged arson.
The man was found in a caravan at the back of the property and confronted police, and during an altercation police fired a Taser stun gun, but it was ineffective.
The man then pulled out a gun which led to two officers shooting him.
Waitemata police district commander Superintendent Bill Searle told a press conference last night that the Taser was "not effective".
The Independent Police Conduct Authority would be investigating and police would be conducting their own inquiries.
The man was arrested for assault and was under police guard at the hospital, where he was in a stable condition today.
Several of the officers were armed at last night's incident, Mr Searle said.
Mr O'Connor told NZPA today that the reason the Taser failed was unknown, but it could be due to protective clothing worn by the offender or both Taser prongs not meeting the offender's skin.
Tasers were not designed to be used against armed offenders.
"There are times when a firearm is absolutely the only option," he said.
The incident could have turned out a lot worse, like the shooting of two patrol officers by an armed man in Christchurch less than a week ago, where a Taser also failed, Mr O'Connor said.
Dog-handler Senior Constable Bruce Lamb was shot in the face and Constable Mitchel Alatalo was shot in the thigh while carrying out routine inquiries in suburban Phillipstown on July 13.
Six-year-old police dog Gage was shot dead in the incident.
That shooting -- the ninth police shooting in two years -- showed the current policy on police firearms use was not working, Mr O'Connor said last week.
"Whatever we're doing now is not working, so certainly we're going to have more people on the frontline armed."
Last night's incident highlighted "the number of criminals out there who have firearms and are prepared to use them against police", he said.
Last week, Police Minister Judith Collins and Police Commissioner Howard Broad gave their support to a review of the current firearms policy, due before Christmas.
"Our officers are facing increased risk, we owe it to the safety of the officers to give them the tools to do the job and back their judgement...It seems an increasing number of people are willing to take on the police with firearms," Mr Broad said.
