A bus, with a number of passengers on board, and a milk tanker crashed about 3.35pm, killing the male bus driver.

The male driver of the bus died at the scene.

A number of passengers on board the bus at the time have suffered minor injuries and are receiving treatment by Ambulance Paramedics.

The driver of the truck will undergo mandatory drug and alcohol testing.

Police and other emergency services from Glen Innes were called to the Gwydir Highway.

It is understood the Westpac Life Saver Rescue Helicopter - Northern Region has been called to the scene.

Local detectives and specialist investigators also are on the way.

An investigation into the circumstances surrounding the incident is underway, and a report will be prepared for the coroner.

The Gwydir Highway between Glen Innes and Grafton is closed and diversions are in place. Lengthy delays are expected and drivers are advised to avoid the area.

Anyone who witnessed the crash or has information that could assist police with their inquiries is asked to contact Inverell detectives or Crime Stoppers on 1800 333 000.