A 59-year-old man remains in a serious but stable condition after he was ejected from his tanker loaded with bitumen, which rolled onto the centre median strip of the M1 at Berowra.
A Careflight spokesman said the man was ejected from the semi-trailer and trapped beneath the cabin shortly after 12.30pm, his arm was reportedly pinned and partially submerged in pooling water following the incident.
"CareFlight's rapid response rescue helicopter flew to Berowra shortly after 12.30pm," the spokesman said.
"Heavy rain and low cloud led the helicopter to dispatch the critical care medical crew at a nearby oval to meet a police car. "CareFlight's specialist doctor and intensive care paramedic were quickly conveyed to the scene, where they assisted the man, who remained trapped for about 45 minutes."
The truck was carrying about 20 tonnes of bitumen according to the Careflight spokesman, which blocked traffic in both directions.
Two southbound lanes of the M1 Pacific Highway are still closed and queues are stretching as far as 9km following the accident.
NSW Police are reporting that all northbound diversions off the M1 and onto the Pacific Highway have been lifted, but two of the three southbound lanes remain closed.
Northbound traffic remains heavy.
Emergency services, Roads and Maritime Services and a Fire & Rescue NSW HAZMAT team worked to free the 59-year-old man before he was taken by road to Royal North Shore Hospital.
"The man is under the ongoing care of CareFlight's doctor and paramedic, along with NSW Ambulance crews," the Careflight spokesman said.
A Transport Management Centre spokeswoman said both north and southbound lanes were closed for up to an hour as a result of the incident.
A NSW Police Media spokesman said motorists are being urged to delay all non-essential travel in both directions following the crash a short time ago.
"The crash happened about 12.25pm when a tanker loaded with liquid bitumen rolled over," the spokesman said.
"All emergency services are in attendance including Fire & Rescue NSW HAZMAT officers who will assess and clear the site.
"Traffic in the area is heavy and motorists who cannot delay travel should expect significant delays."
For the latest traffic information visit www.livetraffic.com or call 132 701.