State Highway 25 is closed between Hikuai and Whangamatā, while emergency services respond to a serious crash.
The crash involving a car and a motorcycle was reported at 12.45pm, around 3 kilometres south-east of the SH25A turnoff, on SH25.
Initial indications are that there have been serious injuries.
Motorists are advised to avoid the area while the road is closed, which is until further notice and may be for the rest of the day.
Updates will be available on the NZTA/Waka Kotahi Journey Planner website.