The incident is the third death in less than a week in the suburb of Ranui.
Yesterday's shooting came two days after a double stabbing at a home in nearby Pooks Rd in which Farhat Rana Malik and her daughter, Sidra Noor Malik, were killed.
Detective Inspector Bruce Scott said there was no indication the two incidents were related.
Officers were investigating a possible gang link in relation to yesterday's shooting.
"That's part of what we're looking at, to see if they've got associations to gangs, but at the moment we can't say," he said. "We are speaking to people in the vicinity, neighbours and the like, trying to piece together at the moment what's taken place and why."
The dead man was found on Luanda Drive and was a resident of the street, Mr Scott said.
After the shooting, two people drove the injured man to hospital.
Their bloodstained car was later pulled over by police in Triangle Rd and seized for forensic examination.
The two occupants were assisting police with their inquiries, Mr Scott said.
Police believed more than one person fired shots. He confirmed that a firearm had been found at the scene.
A man, who declined to be named, said he was at the Waitakere Hospital accident and emergency unit when one of the victims was brought in.
"It was a pretty freaky experience. Lots of shouting and swearing. And heaps of blood. The guy they brought in was face down on the stretcher covered in blood."
Birdwood School, which is close to Luanda Drive, went into lockdown after yesterday's shots were heard.
Meanwhile, Ishrat Malik, 55, has been charged with the murders of Rana Malik, aged in her 50s, and Sidra Noor Malik, believed to be in her teens, in the Pooks Rd stabbings.
He appeared in the Waitakere District Court on Tuesday and was remanded in custody until next month.
