A FIERY crash between a B-double truck and a mobile crane is blocking all northbound lanes on the M1 Pacific Motorway at Brooklyn, north of Sydney.
The two drivers escaped serious injuries in the accident at 4am on the motorway about 2km south of the Hawkesbury river.
Both vehicles were travelling north when they collided.
But their badly damaged vehicles are still blocking all lanes between the cliff face and median strip.
The accident also caused a scrub fire on the median strip which has now been extinguished.
One driver was taken to Gosford Hospital with minor injuries, while the second driver miraculously escaped unharmed.
NSW Police Inspector David Hogg said both vehicles were destroyed.
"The drivers of both vehicles are extremely lucky to be alive," Insp Hogg said.
"The B-double has suffered some significant crash damage to the front as well as fire damage has completely destroyed the front of the B-double.
"The crane has suffered some significant damage aswell and has been knocked onto its side."
Traffic has been backed up for 14 kilometres and authorities are advising motorists to use the Pacific Highway.
The highway is expected to be closed for a few hours as an extensive clean up operation gets underway.
Northbound traffic is being diverted via the Old Pacific Highway.
Southbound traffic is not affected.
Update your news preferences and get the latest news delivered to your inbox.