A ute has flipped into the ditch on State Highway 3 near Kaitoke.
Police spokesman Gareth Thomas said police were called at 3:50pm by a member of the public who said the driver "was out of the vehicle".
The driver declined to be seen by an ambulance and was believed to be fine, Mr Thomas said.
Witness Carey Wood said: "I just came around the corner and there it was on its roof."
He said there was no sign of the driver or an ambulance.
Tow trucks are at the scene and the road has been reduced to one lane while the vehicle is removed.