Greta Valley truck rollover

Two trucks have collided on Greta Road, Greta Valley, in Hurunui around 9:10am.

One truck has rolled and the driver is believed to be in a critical condition.

"Fire and Emergency NZ and ambulance are also at the scene," says a police spokesperson.

"Diversions are being put in place and the road may be closed for some time.

"The Serious Crash Unit are attending the scene."