Olympic gold medalist Cathy Freeman and her family are in shock over the sudden death of her brother.

Norman Freeman, 34, was a passenger in the front seat of a car that swerved off the road and slammed into the back of a truck in Mackay.

He died at the scene.

Freeman was in transit at Brisbane airport en route to visiting a school on behalf of the Catherine Freeman Foundation when she was told the news, Freeman's manager Carolyn Schuwalow said. "She is now with her mother and family in Brisbane,'' Ms Schuwalow said in a statement issued on behalf of the family.

"Catherine wishes to thank all Australians who have offered support and sent in their condolences. She has asked that her family's privacy be respected at this time.''

Family friend Tanna Corowa told the Seven Network: ''(Norman) was a champion lad ... just like his sister, just talented.''

Police said a man died when a vehicle swerved off Slade Point Road, near a school and continued into a parking area where it hit a parked truck about 5.20pm (AEST).