Whangārei police are investigating the death of a motorcyclist just south of the city overnight.
Detective Senior Sergeant Shane Pilmer said a member of the public found a motorbike on the side of Otaika Valley Road, or State Highway 15, just before 5.30am on Wednesday.
The motorcyclist was then located deceased in a creek next to the road.
Pilmer said the investigation was in its early stages, and the man's death was at this point being treated as unexplained.
State Highway 15 would remain closed between Otaika and Maungatapere while a scene examination was carried out, he said.
Residents who needed to access their properties along the closed stretch of highway should approach uniformed staff at the cordon, Pilmer said.
He urged anyone who travelled through State Highway 15, or Otaika Valley Road, early on Wednesday morning to contact police if they saw anything unusual.
Information could be passed to police by calling 105 and quoting reference number P061439912.
NZTA said a diversion had been set up via State Highways 1 and 14, with State Highway 15 expected to remain closed for much of the day.
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