A fiery crash between a truck and a mobile crane has closed the north-bound lanes of the M1 Pacific Motorway north of Sydney, causing extensive delays for motorists.
The B-double truck erupted into flames following the collision with the crane near the Pacific Highway overpass at Brooklyn about 4.05am on Tuesday.
The large blaze also spread to the scrub on the median strip, police said.
An hour after the crash, motorists were stuck in a four-kilometre traffic jam leading up to the crash scene. Just before 6am, that queue had grown to 12 kilometres, the Transport Management Centre said.
A NSW Police spokeswoman said the cause of the crash was not yet known, but a witness claimed one of the vehicles had jackknifed.
She said both drivers had been accounted for. One of the drivers was taken to hospital with minor injuries, the spokeswoman said.
The TMC said the north-bound lanes of the motorway were expected to remain closed for "some time".
North-bound motorists are advised to delay travel or, if necessary use the Pacific Highway as an alternative route and allow plenty of additional travel time.