State Highway 1 is partially closed east of Blenheim after two trucks collided, causing masses of grapes to spill onto the road.
Shortly before 5.30pm, police said the road winding through the heart of Marlborough wine country was expected to be closed for several hours into Saturday evening, after the two truck smash earlier in the day.
Motorists are asked to avoid State Highway 1 at Riverlands, near Cloudy Bay Dr.
Traffic management is in place. There is reported to be heavy traffic in the area.