A hazardous substance from a truck that crashed on State Highway 49 near Ohakune needed multiple fire crews from Whanganui and the Ruapehu area to deal with it.
A police spokeswoman said a truck and trailer unit went off the road on Tohunga Road near Old Station Road at 3.10am today.
The crash left the trailer partially on the road with the rest down a bank on State Highway 49 near the intersection with State Highway 4, closing SH49 for most of the day. A crane was needed to tow the vehicle, the spokeswoman said.
Fire and Emergency Whanganui Station Officer Jason Hamlin said Whanganui crews were called in to help with a "chemical incident" which was initially attended by Ohakune's volunteer brigade.
Two Whanganui crews were attended in the early hours of Tuesday and another two crews relieved them during the day, Hamlin said. Hazmat units were also called to the scene.
Hamlin, who was on another crew called in to cover the Whanganui fire station, did not know what chemical was involved.
St John spokeswoman Chrissy Hamilton said the truck driver received moderate injuries and was taken by ambulance to Whanganui Hospital.