A State Highway 29 lane near Matamata is blocked by a truck and trailer unit that has locked-up.
The truck is stuck about 600 metres to the east of the intersection of SH27 and SH29.
There is heavy fog in the area and traffic westbound on SH29 is being forced to double over yellow lines to pass the truck.
Police are advising motorists to drive with caution in this area and to expect delays there.