Police would not say if they had located the gun used to wound the man.
The officer thanked New Lynn residents for their understanding after a morning of disruption.
Multiple cars have been seen rushing to the New Lynn area, while the police helicopter circled overhead.
“We believe he was shot at the house but we’re working to determine the exact circumstances and who was involved.”
Earlier, two women could be seen at the front of the property.
Police were earlier seen dusting for fingerprints on a window sill adjoining a shared driveway.
The curtains of the modest family home remain drawn into the afternoon.
Hutchinson Ave had now come out of lockdown, but a short time ago up to six police cars as well as armed police remained outside the brick home, which was still taped off.
A spokeswoman for St John said paramedics treated the patient with serious injuries on Great North Rd in Te Atatu South at about 9.43am.
The man has since been taken to Auckland Hospital.
An abandoned vehicle was also photographed at the scene.
Media outlet RNZ reports armed police swarmed a carpark at a mall in the area.
According to the report, startled shoppers said two police cars approached a parked vehicle before officers slowly advanced towards it with weapons drawn.
Police also earlier said they separately locked down Hutchinson Ave in New Lynn.
A resident in one of the street’s houses said armed police shut down the area just before 10am as he returned from a walk with his daughter.
“We were just doing our normal Saturday routine and all of a sudden there’s two police officers came down the [neighbouring] driveway with rifles asking us to hide,” he said.
Later he heard police using a microphone to address a person in a nearby home in the street.
“They were on the loudspeaker saying, ‘We have armed police, please come out with your arms up’,” he said.
He said there were still armed police in the driveway next door and what looked like detectives out the front of his home but the street had been quiet for the last 30 minutes.
A police spokeswoman said, “Police were called at about 9.40am today, and are working to establish the circumstances leading to the incident. One person has been taken to hospital with serious injuries.”