Driver's lucky escape after truck plunges down embankment into creek

Emergency services were called to the M1 at about 3am on Tuesday after reports a large truck had crashed about 500 metres north of the Karuah Bridge.

Port Stephens Hunter police were tasked to the scene and found a B-double truck had rolled down an embankment and fallen into a creek.

The two trailers attached to the truck were on a grass median strip, police said.

The 53-year-old man behind the wheel of the truck was not injured in the crash and returned a negative result on a roadside breath test.

Officers at the scene were told the truck had been overtaking another heavy vehicle, when that second vehicle began veering into the B-double, forcing the driver to "take evasive action", police said.

An investigation has been launched into the circumstances surrounding the incident.

Police have issued a public appeal for help and have urged anyone with dashcam footage or information to contact police or Crime Stoppers on 1800 333 000.

The truck crash was holding up traffic on the Pacific Highway on Tuesday morning, with southbound lanes closed as emergency crews worked to retrieve the heavy vehicle.

Southbound traffic, heading towards Newcastle, was being diverted through Karuah and that detour was expected to remain in place into the afternoon.

Emergency services, Transport for NSW, a heavy vehicle tow truck and a crane were at the scene at about 9am on July 2.

Real-time traffic updates can be found on the Live Traffic NSW website or phone app.