Police have named the man who died after he was taken to Whangarei's St John ambulance station as 37-year-old Far North man John Henry Harris, also known as John Boy.
Mr Harris, a patched member of the Tribesmen Motorcycle Club, died in an ambulance at Whangarei's St John station after a dash to get him medical help.
A post-mortem examination confirmed Mr Harris died as a result of a gunshot wound to the chest.
Detective Inspector Kevin Burke said officers want to hear from anyone who may have seen two vehicles they believe will help with the investigation.
The first vehicle is a red 2007 Holden Commodore GTS registration JCS248 which was towed from Hassard St early Tuesday morning.
The second vehicle of interest is a black 2011 Holden Commodore SS registration FZC162 which was located on fire in Lovell Rd, Ruatangata about midday yesterday.
"We believe it is a gang incident, however we believe it is an internal incident involving members of the Tribesmen Motorcycle Club," Mr Burke said.
"We understand this may have been ignited as the result of simmering disputes involving a vehicle."
Police believe the incident was not connected to the death of Moses Mahanga who was found dead in a vehicle in Otangarei on William Jones Dr on October 4.
Mr Burke said police have persons of interest they are keen to locate.
A relative of Mr Harris earlier said he was loved by many and came from a loving family.
"The sad thing about gangs is they have gone from one extreme to the next," she said.
"The change from cannabis to P has contributed to this. Users have lost the ability to make right decisions, [it's] so much more complex. Actually, people need to be educated about that too."