Three dead after single car crash in north-eastern NSW

Two women and a man have died after a single car crash in north-eastern NSW.

Emergency services responded to the crash on the Kamilaroi Highway, near Curlewis, about 20km south of Gunnedah about 6.30am.

Three back-seat passengers died at the scene and are yet to be formally identified.

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NSW Police previously reported three men had died, but they have since clarified that two women and one man died.

The driver, a 24-year-old man, was not injured and has been taken to Tamworth Hospital for mandatory testing.

"The front passenger, a woman, was treated by NSW Ambulance paramedics before she was airlifted to John Hunter Hospital in a serious condition," NSW Police said in a statement.

The Kamilaroi Highway is closed between Curlewis and Gunnedah while police investigate.