Truckie dies as M1 crash sparks explosion and bushfire

A man has died after three trucks and a car collided, sparking a fireball and causing traffic chaos on the M1 in the NSW Lake Macquarie region.

At about 12.50pm today, the trucks - including a tanker carrying ethanol - collided on the M1 motorway at Cooranbong.

A car was also damaged in the crash.

Police tonight confirmed the male driver of one of the trucks died at the scene. He is yet to be formally identified. 

The collision sparked a bushfire north of the crash site after the ethanol tanker exploded.

"The rear compartment of the ethanol tanker actually breached and caught alight," Greg Windeatt from NSW Fire and Rescue said.

"It then from that fire involved the middle compartment and that's what we're currently working on."

The M1 was closed in both directions from about 1km south of the Freemans Drive interchange.

One northbound lane has since reopened but all southbound lanes remained closed as the salvage operation continues.

Motorists are advised to delay their travel of avoid the area. 

Road diversions are in place but significant delays are to expected for up to six hours.

Soutbound traffic is queued more than 12km, adding an extra 100 minutes to travel times, while northbound motorists are being forced to wait 90 minutes in an eight-kilometre queue.

Authorities are also urging anyone with helpful information in relation to the crash to contact Crime Stoppers on 1800 333 000.