Queensland riders Baylee Nothdurft and Todd Banks have been injured in a trackwork fall at Toowoomba.

Both were taken to hospital and apprentice Nothdurft was treated for a knee injury and possible broken leg.

Banks suffered a suspected broken arm and facial injuries.

Chief steward Allan Reardon said the pair were apparently riding fast work when another horse spooked and collided with them but an investigation would be held later to determine what exactly happened.

"A third trackwork rider was able to walk back to the enclosure but she later went to hospital to have an arm checked for any serious injury," Reardon said.

Another Toowoomba rider, apprentice Nick Keal, broke a collarbone while riding work last Thursday.