Detectives are now working around the clock to bring justice to the Hart's family, McNaughton said.
"We are well aware that there are people in the community who know those involved and what they have done.
"Now is the right thing to do and contact police with what they know."
A homicide investigation, dubbed Operation Metals, is in its fifth day. No arrests have been made.
A scene examination and post mortem examination have been completed.
On the day of the shooting, Great North Rd was closed between Rata St and Fruitvale Rd, causing traffic chaos.
Houses in Green Bay were also searched by police, assisted by the Armed Offenders Squad, as part of the investigation.
The fatal shooting "scared the living daylights out of" New Haven Motel staff who were cleaning a room 2m away from where Hart died.
He was found injured on the driveway of a property on Great North Rd in New Lynn on Friday just after 10am, after police received reports of a firearm being discharged.
Police tried to perform first aid but Hart died at the scene.
"A girl was cleaning a room right next door, about 2m away from where it happened," a staff member told the Herald.
"I thought it was a firework. I said: 'No, no it's only a firework' and she said: 'No someone has got a gun and they just shot that guy there'," the staffer said, who the Herald has agreed not to name.
Before the alleged shooting, a car was seen driving into the motel car park. Staff asked the driver to leave.
"This car drove in, parked across from the reception, it looked like one of the units' [guests], but I knew they weren't in there because the people had left," the staff member said.
"I went to tell them 'listen you can't park here' ... then slowly they turned off, they went to the front of the gate where the letterbox is and everyone got out of the car."
Staff have shared CCTV footage with police and say the property has attracted police attention many times in recent years, affecting their business.
• Anyone with information is urged to contact the Operation Metals inquiry team direct on (09) 839 0602, or to call Crime Stoppers anonymously on 0800 555 111.