Ambulance NSW said four paramedic crews and the Westpac Rescue Helicopter were tasked to the scene on Wallabadah Creek Road at Wallabadah about 9.30am.

Paramedics found a woman, believed to be 19, had been thrown from the wreckage of the single-vehicle accident and suffered significant facial injuries and suspected pelvic injuries, a spokesperson said.

She was airlifted to John Hunter Hospital in Newcastle by the chopper while a second patient, who suffered minor injuries, was taken by road to Tamworth hospital in a stable condition.

Police remained at the scene for much of the day and are investigating the cause of the crash.

Meanwhile, a truck driver has been taken to hospital in a stable condition after his semi-trailer overturned on the New England Highway near Goonoo Goonoo.

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The driver suffered head injuries in the crash just before dawn on Monday, 20km south of Tamworth. 

The crash shut the road and saw Fire and Rescue NSW and RFS crews, along with the RMS, deployed to the scene.

The road re-opened mid-morning.

Investigations are continuing, police said.