Auckland police say the two people shot in the CBD late last night "weren't looking for trouble", but are assuring the public it was an isolated incident.
Police were called to reports of a fight on the corner of Fort and Queen streets about 11.30pm on Thursday.
A small group of people were witnessed fighting before an offender pulled out a firearm and fired several shots.
One person was shot in the head and a second person was hit in the abdomen, and both were taken to hospital in critical condition.
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Detective Senior Sergeant Craig Bolton said one of the victims remained in a critical condition, while the other was now stable.
Bolton said those living and working in the CBD may be feeling vulnerable and police had no tolerance for violence in public places.
"The CBD is still a safe place and I encourage people to come to the CBD."
He said police could not outline what the investigation team was doing.
"Due to operational sensitivities, we are unable to provide any further detail at this stage, but will do as more information becomes available."
Whether the incident was gang-related would form part of the investigation.
"At this stage, I can say we are following positive lines of inquiry with a CCTV phase and that is helping," Bolton said.
The person who fired the shots was wearing distinctive red and black pants and a red hat, and fled the scene on a scooter.
Bolton said the offender was on the Lime scooter before and after the incident.
He said the number of people involved in the incident on both sides was part of the investigation.
"Two groups were unknown to each other and the rest of it is forming part of our ongoing investigation."
He said he had to hold back information about the type of firearm used due to operational sensitivities.
The number of shots fired was part of the investigation but "could be up to four" and early indications were there was only one firearm.
He said the CCTV footage made it clear to police that it was an isolated incident.
"Just to help reassure the community, there were words exchanged, so then the person gets off the scooter and confronts the other group and then things escalate from there, so that's how we're confident it's an isolated incident."
He had no doubt there would be more police in the CBD.
"I'm very concerned for the victims who were going about their own business. They weren't looking for trouble, and our job is to locate the offender and hold him responsible."