A police spokeswoman said the incident started with a police pursuit on the southern motorway, which was called off due to high speeds.
Police said the pursuit on the motorway was called off at 12.30pm due to speeds in excess of 170km/h.
The vehicle left the motorway at Manurewa, and was followed at a distance by police units.
A man was seen getting out of the car with a firearm and pointing it at the patrol vehicle.
The man then walked to another car at the start of the line of traffic, driven by a member of the public, and forced them to drive him to an address in Takanini.
The address was quickly cordoned by police and a man was apprehended nearby.
The house contained nine other occupants, all of whom have been removed, and the scene was searched by the Armed Offenders Squad for the firearm, which was located with a large amount of ammunition.
Trains on the Southern Line were stopped while the search was taking place, but are now running again.
Road blocks around Manuroa Rd have also now opened.
Incident Controller Senior Sergeant Kai Shao of Counties Manukau Police has commended the actions of police involved.
"This is a serious event involving a member of the public and it's noteworthy that no one was injured in this incident.''
Residents had been posting photographs of armed police guarding road blocks in the area.
Mehpara Khan said on Twitter that police had blocked several exits from Manuroa Rd, but Takanini School Rd remained open.
She posted photographs of police officers blocking roads, and an officer standing guard on a railway pedestrian crossing.
Another local resident said there were about 15 police cars in the area, and streets near the corner of Taka St and Great South Rd had been cordoned off.
