Four paramedic crews, police, the Westpac Rescue Helicopter, Medowie Rural Fire Brigade and the Port Stephens unit of the State Emergency Service were all called to the intersection of the Pacific Highway and Medowie Road about 11.30am after a sedan and truck collided.

The two male occupants of the car died at the scene, police said. They have not yet been formally identified. It is believed the men were aged in their 70s.

Police said the driver of the truck was not injured but had been taken to John Hunter Hospital for mandatory blood and urine testing.

Officers from Port Stephens-Hunter Police District have established a crime scene and are investigating the circumstances surrounding the crash.

A report will be prepared for the Coroner.

The Pacific Highway was closed in both directions following the crash but contraflow was quickly established, allowing northbound traffic to pass through.

Southbound lanes remained closed until about 5.30pm on Tuesday, when the Transport Management Centre said a single southbound lane had reopened.

Traffic is still heavy on the Pacific Highway. Motorists are being advised to allow extra time in their travel plans.

Stay up to date on the traffic conditions here: www.livetraffic.com