A teenager has been struck and killed by a school bus in the Hunter Valley in what has been described as "an incredibly distressing scene".

Emergency services were called to Mount Hall Road, near Clyde Circuit at Raymond Terrace, just before 8.30am to reports a boy was riding his bike when he was hit by a Hunter Valley Buses vehicle.

The bus was full of students on their way to school.

Road closures have been put in place on Mount Hall Road between Closebourne and Banks streets. Credit:Fairfax Media

Police, paramedics, Fire and Rescue and the speciality rescue unit from Port Stephens SES raced to the scene.