The Pacific Highway is closed southbound north of Newcastle after a semi-trailer truck crashed down a steep embankment early this morning.
The B-double loaded with mixed goods crashed off the southbound lanes of the highway 500 metres north of Karuah River Bridge just after 3am, according to police.
The truck rolled down the steep slope and into a creek, with two trailers attached to the vehicle on the grass median strip.
The 53-year-old male driver escaped injury.
He underwent a roadside breath test and returned a negative result.
Police were told the heavy vehicle had been overtaking another truck, when the second vehicle began veering into the B double, forcing the driver to take evasive action.
A diversion has been set up for all southbound traffic via Tarean Road (the old highway) through Karuah, which is expected to remain in place until this afternoon.
Heavy machinery is being brought in to salvage the truck.
Drivers are being urged to allow for extra travel time.
Police are appealing for anyone with dashcam footage of the incident to contact Crime Stoppers on 1800 333 000.
