The road was earlier closed between the SH16 roundabout and Joseph McDonald Drive but had since reopened.
However, police remained in the area and warned motorists to expect delays.
Police were conducting a scene examination this morning and working to find the shooter.
"We are trying to establish exactly what happened in the lead-up to this incident, so anyone who might have any information is encouraged to call Waitemata Crime Squad on 09-839 0697 or report anonymously via Crimestoppers on 0800 555 111," Murray said.
