Two people are dead after a horrific truck fire on the M1 motorway north of Sydney.
All northbound lanes and one southbound lane are closed, with at least three cars involved in the accident.
The collision between a truck and several cars happened about 5pm on Tuesday at Mooney Mooney Creek.
The incident caused the truck to catch on fire.
A number of emergency crews have responded, treating at least six patients at the scene.
Police have confirmed two of those patients have died.
Two women managed to walk away from their cars and are in a stable condition with impact injuries at Gosford Hospital.
The truck driver’s injuries are more serious and he has been rushed to Sydney’s Royal North Shore Hospital.
Reports from the scene suggest a car may have pulled in front of the truck, just before it flipped.
Police will remain at the scene for some hours, piecing together precisely what occurred.
Significant traffic delays expected
Traffic was being diverted at Calga off the Pacific Highway northbound onto the Old Pacific Highway, Ken Kanofski from Roads and Maritime Services said.
“Recently one lane has been opened past the crash scene to clear traffic stuck between Calga and the crash site,” Mr Kanofski said.
“When that traffic’s cleared, we’ll be able to split the traffic at Calga, that will give us two lanes going northbound.
“We’ll be able to put one lane on Old Pacific Highway and one lane on the M1.”
Roads and Maritime Services advises motorists to delay their journey or catch a train through the affected area if possible.