Two cars collided on Thomas Mitchell Drive just south of the Mount Arthur turnoff at about 5.00am on Thursday.
It's understood one the cars is on it's side and Thomas Mitchell Drive is blocked in both directions.
NSW Ambulance says no-one has been seriously injured.
Meanwhile, a petrol tanker has jackknifed and collided with the rear of a car on the Hunter Expressway near Heddon Greta.
The crash is affecting northbound lanes and motorists are being advised to proceed with caution.
It's understood the petrol tanker is empty but around 30 litres of hydraulic oil has spilled onto the road.
