An elderly man is in a critical condition after a serious two-vehicle crash in the Lower Hunter overnight.
Emergency crews were called to the Hunter Expressway near Seahampton about 8.30pm on Thursday after reports of the smash.
Police said on Friday morning that officers had been told the two cars collided before hitting the expressway's dividing barrier.
The driver of one vehicle, a 79-year-old man, was trapped for a short time before being released and taken to John Hunter Hospital in a critical condition.
Police said he was in surgery on Friday morning.
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The driver of the second vehicle, a 30-year-old man, was taken to John Hunter Hospital for mandatory testing.
A crime scene has been established and the Crash Investigation Unit will investigate the circumstances surrounding the incident.
Traffic delays are expected with both eastbound lanes on the Hunter Expressway closed and traffic being diverted onto John Renshaw Drive.
Westbound traffic is being diverted into the breakdown lane.
As inquiries continue, police urge anyone with information about the crash, or who may have dashcam footage, to contact police.