The two men - who did not know the boy - didn’t bother checking if he was OK or if they could help him but ran off.
Police said the accident took place at around 11am on the Star Jet 1 chairlift at Flachau Griessenkar resort.
The boy was visiting with a school group for a skiing holiday. When the men opened the safety bar he slipped out of his seat, fell around five metres and landed in the snow. He broke his forearm and suffered serious abrasions to his face.
Witnesses rushed to help the injured boy and called the emergency services. A snowcat was used to take the boy to hospital. There was no trace of the two men who caused the accident.
A 13-year-old schoolboy from Germany was also injured on Wednesday when he collided with a 55-year-old skier from Berlin, on the Hochalmbahn in Obertauern.
The teenager seriously injured his knee and was rescued by a ski patrol.