Emergency services are attending a serious incident at Bulls where a truck has rolled near the intersection of Raumai Rd and Parewanui Rd.
A police spokeswoman said initial reports are that the driver may be trapped but details of any injuries are unknown.
It is not yet known what type of truck is involved.
Emergency services, including police, fire and ambulance crews, were called to the incident about 12.25pm.
The road is closed and diversions are in place. Motorists are asked to avoid the area.
