A spokesman said police responded to reports of gunfire outside a house in Glendene, West Auckland on Friday afternoon.
When police arrived, two people were found dead.
Police then blocked Taikata Road on the Te Atatū Peninsula, where a man was taken into a handcuffed police car.
Detective Inspector John Sutton said a man has been remanded in custody after the incident and a homicide investigation is underway.
“He’s being talked to in relation to the two deaths,” Sutton said.
The roadblocks will remain in place on Barry’s Road, and locals will see an increased police presence in the area.
“Police understand that this was an alarming incident for local residents and we would like to assure the local community that we are not looking for anyone else at this time.”
A resident of Barry’s Road said her husband witnessed the shooting.
“He heard the gunshot, so the woman screamed, and then they escaped in a car,” she said.
“It’s awful. He’s going to hear those screams for a while.”
Another resident nearby said the road had been blocked off and that armed police were on the street.
He said there were four ambulances at the scene.
A resident of the Te Atatū Peninsula said the driveway to Taikata Road was blocked by a marked police car at the roundabout where it connects Te Atatū Road.
At least a dozen police cars had been seen in the surrounding streets on Friday afternoon.
Two cars were parked further up the main road, close to a petrol station.