Armed officers and dog handlers swarmed over two Auckland suburbs yesterday as fake firearms triggered two huge police operations.

An armed offenders unit and dog handlers were among up to 20 officers sent to the first callout, which occurred in Glen Innes about 7am.

Inspector Earle McIntosh said police received reports that a man had got into a fight with fellow guests at an all-night party and threatened them with a shotgun.

The suspect then travelled to a house on nearby Leybourne Circle with several other men.

Police cordoned off all entrances to the street for more than two hours while members of the the armed offenders squad moved in.

After entering the house police discovered the weapon was an imitation.

At least four people were taken to Glen Innes police station for questioning.

Neighbours had been warned to stay indoors, but most said the area was usually a safe place to live.

The second callout was in nearby Mt Wellington shortly before noon, when a man tried to rob a brothel in a private house with a BB gun.

Armed police and at least eight vehicles, including one dog-handlers' vehicle, were sent to the address.

McIntosh said one of the women struggled and received a small cut but the robber fled without getting any money.

Earlier this month a Porsche driver sparked a police pursuit across Auckland's harbour bridge after he was said to have waved a handgun at another motorist.

More than half a dozen police cars chased the Porsche, which was pulled over, but a search of the vehicle revealed the weapon was an airgun.

Police national headquarters superintendent Tony McLeod said at the time he was concerned about the number of police callouts over "people with small brains" carrying around air pistols.

He said police had to respond as if they were real guns as they had no way of knowing if they were replicas.

"People with [replica] handguns should be thankful the New Zealand police are so professional in responding to these situations."