A man has been flown to Dunedin Hospital in a critical condition after his truck crashed near Raes Junction.
A St John ambulance spokesman said the truck rolled on farmland between Raes Junction and Beaumont about 9am today.
A police spokeswoman said it was a fertiliser truck and no other vehicles were involved.
Investigations are continuing.
A WorkSafe spokesperson said it was investigating the incident.
"We understand a truck crashed, leaving the driver with serious injuries. As the matter is now under investigation we are unable to make any further comment."
