ONE person is in a critical condition and another recovering from serious injuries after a horror boat collision in Central Queensland over the weekend.

Police and Maritime Safety Queensland are investigating the crash, which saw two people thrown through the air and occurred at a water skiing event in Emerald on Saturday afternoon.

Police have so far established that at 3.30pm a boat competing in the event at Fairbarin Dam struck a wave and spun suddenly into the path of another boat, causing a crash.

The driver and passenger of the second vessel were thrown from the boat which then struck the occupants in the first vessel, a 54-year-old man and a 30-year-old woman both from the Bundaberg area.

They were airlifted to Royal Brisbane and Women's Hospital, the man with critical head injuries and the woman in a stable condition.

The male occupants of the second boat were recovered from the water without serious injury.

Investigations into the incident are continuing.