A truck driver has died on the M1 Motorway after a crash with another truck at Morisset, about 30 kilometres south of Newcastle.
Emergency services were alerted at about 2:45pm.
Police said in a statement that a male driver died before emergency responders arrived.
The man has not been identified.
The driver of the second truck, a 57-year-old man, was uninjured.
The incident occurred in the southbound lanes of the motorway.
All southbound lanes are closed to traffic and Lake Macquarie Police have cordoned off the area.
Transport Management Centre spokeswoman Bronwyn Martin told ABC Newcastle Drive that the southbound lanes would be closed for a considerable amount of time.
“If you can avoid travelling on the M1 at the moment, that is the best thing to do,” she said.
“If you do need to travel and you are heading south, you’ll be diverted off the motorway.
“There is a police investigation being carried out into this crash, so they will be shut for some time.”
Long queues have built up on the M1. (ABC News)
Ms Martin said one northbound lane was closed to allow emergency and traffic crews to turn around other trucks and vehicles in the area.
The M1, which links Newcastle to Sydney via the Central Coast, is one of Australia’s busiest motorways.
Long queues were reported in the southbound lanes and northbound traffic has also been affected.
Ms Martin said traffic was heavy on Wyee Road and along the diversion route.
“If you do need to travel, be prepared for significant delays,” she said.