A five-year-old boy who was thrown off a carnival ride in south-east Queensland at the weekend has woken from his coma.

Patrick O'Sullivan suffered serious head injuries at a school fete in Highlands, near Toowoomba, west of Brisbane, on Sunday.

He was airlifted to Brisbane's Mater Children's Hospital, and began breathing without a ventilator yesterday afternoon.

Witnesses to the accident described their horror as Patrick was thrown from the ride, hitting a safety fence and landing on the roof of another stall.

Workplace Health and Safety are looking into the incident.