Emergency services were called to the scene, five kilometres north of Boggabri, at 6.45pm after reports two cars had collided head-on.

Police said a Honda Civic sedan with five people on board was travelling north and collided with a Toyota Camry travelling south. 

One man, an 18-year-old passenger in the Civic, was killed, while the driver and three other occupants were injured.

Police said the 18-year-old woman who was behind the wheel was flown to John Hunter Hospital in Newcastle in a serious and unstable condition.

Three other occupants from Narrabri were taken to Tamworth hospital with various injuries.

The driver and only occupant of the Camry, a 48-year-old Karangi woman, suffered minor injuries and was also taken to hospital.

A police spokesperson told The Namoi Valley Independent investigations were under way.

“It’s early days in the investigation at this stage,” the spokesperson said.

“The Crash Investigation Unit are onto it and are looking into the circumstances around the accident.”

On Tuesday morning, a Hunter New England Health spokesperson told The Namoi Valley Independent three patients were still in hospital in a stable condition.

The crash blocked the highway for several hours. The Kamilaroi Highway re-opened on Tuesday morning, following an examination of the crash scene.

Both wreckages were towed from the scene and will be examined.

A report will be prepared for the coroner.