Emergency services were notified of the incident shortly after 6pm.
Stop-go traffic measures will be in place on State Highway 5 near overnight after a landslip earlier blocked part of the road.
It took place in the Ngongotahā area between Western Rd and Paradise Valley Rd, with Fire and Emergency and Police both reporting the incident took place around 6.05pm.
Southbound motorists are still able to travel through, a police spokesperson said, however, they should expect delays.
Northbound traffic was asked to seek an alternative route via Ngongotahā.
The road is expected to be impacted for "several hours" while contractors attend, the spokesperson said.
