A gas tanker has rolled and caught fire after colliding with a truck on State Highway 1 in Greta Valley, North Canterbury.
A St John spokesman confirmed one person had serious injuries and would be flown to hospital by a helicopter.
A freight truck collided with the gas truck near the intersection with Scargill Valley Rd and Valley Rd about 9.10am.
The gas truck had come to a stop on a grassy verge alongside the state highway and gas canisters had fallen around it.