Auckland Mayor Phil Goff says worsening gang warfare is putting innocent people at risk and he warns the city cannot go down the track of "gangland America".

His comments follow a dramatic shooting at a 5-star waterfront hotel yesterday, which police say was linked to an escalating dispute between the Head Hunters and Mongols gangs.

A gun was fired soon after 9am at the Sofitel hotel at the Viaduct, sparking a citywide response with armed officers and the Eagle helicopter.

Detective Inspector John Sutton said the incident - described by witnesses as "a moment of terror" - was linked to a shooting at the Head Hunters' gang pad in Mt Wellington last weekend.

Goff told the Herald it was "intolerable that gangs are carrying out their feuds in public using firearms and risking public safety".

"It really is important that New Zealand not go down the track of gangland America and zero tolerance is now shown to gangs employing firearms against each other or anybody else."

While police were yet to make arrests, Goff said they were pouring massive resources into the investigation and officers believed they knew the culprits' identities.

Police outside the Sofitel in the Viaduct Harbour responding to a firearms incident. Photo / Jason Oxenham

Goff said he hoped those responsible were bought swiftly to justice and that subsequent convictions and sentences reflected the seriousness of the crimes.

"There has to be a clear message that Aucklanders, New Zealanders and police are not prepared to tolerate this kind of behaviour, of factions involved in criminal activities warring with each other."

The escalating violence was a stain on the city's reputation and undermined people's basic right to feel safe in their city.

"What we don't expect in downtown Auckland is to have squads of armed police sorting out gangs who are at war with each other over who owns the patch."

He acknowledged the arrival of so called "501" deportees from Australia was fuelling the turf war as gangs like the Mongols and Comancheros gained in numbers and strength.
"They're treating this like the Wild West."

Goff also acknowledged the arrests of three men yesterday in connection with the fatal shooting of Favona grandmother Meliame Fisi'ihoi, who was gunned down in an apparent case of mistaken identity in January last year.

While the arrests were "a long time coming", Goff hoped they would bring some conciliation to Fisi'ihoi's family.

And he praised police for their "extraordinary efforts" in tackling the broader problem of gun violence and organised crime, including raids on houses and seizure of weapons, restraining criminals' assets under proceeds of crime legislation and a police campaign to crack down on firearms.

Finally, Goff called on members of the public who had knowledge of illegal firearms or criminal activities to share that information with police, who could not tackle the problem on their own.