Local Dr Urie Bezuidenhout - a former South African military member - heard a sound "like a loud zipper", which he believed was too fast for a conventional firearm.
An officer told him the house - which locals believed was gang-affiliated - had been "peppered with bullet holes", Bezuidenhout says.
He was surprised at the police response on Saturday, saying they had left the scene after just a few hours.
"I'd really like to know if they think their response was proportionate," he told the Herald.
"This is so unusual and if it bears out that different weapons were used, then they need to be a bit more responsive and not so flippant about it."
A police spokeswoman confirmed today inquiries were continuing and a scene examination was underway.
Nobody was taken into custody overnight, she said.
There has been an escalation in gang incidents in recent years, particularly in Auckland.
Nearly 350 patients were treated for firearms injuries since January 2016, according to figures released to the Herald by Auckland's three district health boards.
Police say they have zero tolerance for gun violence.
Auckland mayor Phil Goff said recent shootings and gang-related crime were "completely unacceptable and should not be tolerated".
Another suspected firearms incident was also reported in nearby Manurewa on Saturday afternoon.
At 2.48pm police were notified a firearm had been sighted on Russell Rd.
Police attended and cleared the address but did not find a gun, according to a spokeswoman.