A teenager whose legs were severed after he was struck by a train on NSW’s mid-north coast has died in hospital.

The 18-year-old was struck at a railway crossing in Taree in the early hours of December 21 and died at John Hunter Hospital around midday on Christmas Eve, a police spokeswoman told the AAP.

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It was believed the 18-year-old had been celebrating his birthday with family and friends at a nearby home and was struck by the train about 4.30am.

The train driver stopped the train and contacted emergency services.

While police investigated the scene, a group of people threw rocks at them and the 33-year-old train driver, forcing them to take refuge in the driver’s cabin.

Police said paramedics were also blocked, pushed and verbally abused by the group during their initial attempts to treat the teen.

Investigations into the incident are continuing.