The victim had suffered "knife wound injuries," a police spokesman said, and was taken to Auckland City Hospital in a serious but stable condition.
At the scene yesterday, a silver car was seen with blood splashed on part of the passenger-side door, as well as the back door on that side of the vehicle.
Officers were seen retrieving items from the vehicle and looking into nearby wheelie bins.
The area was cordoned off as police officers photographed the car and examined the area.
Part of Station Rd - between Walls and O'rorke Rds - was closed about 3pm as a result. It was reopened about half an hour later.
The circumstances of the incident are not yet known, but authorities said inquiries were still ongoing.
The injured man remains in hospital today, police said.
INCIDENT - STATION RD, PENROSE - ROAD CLOSED - 3PM Due to an incident Station Road in Penrose is CLOSED between Walls Road and O'Roke Road. Follow the short detour or avoid the area if possible. Expect diversions to bus services normally operating along this route. ^MF pic.twitter.com/phJD7paO9p