Five racehorses involved in the Magic Millions sale in Queensland have died after a livestock truck crashed in the NSW Hunter region.

Two men suffered non-life threatening injuries when the truck crashed into a tree about 6.30am on Saturday on the Golden Highway near Jerry Plains, south of Muswellbrook.

Five horses being transported in the truck were killed.

The 62-year-old driver and a 59-year-old passenger were treated at the scene and taken to John Hunter Hospital in a serious condition.

The names of the racehorses have not yet been revealed.