The boy was injured when a "freak" gust of wind swept the 14-year-old and Adrenalin Skydive instructor Tony Rokov into an uncontrollable freefall about 10 metres above the ground, the group's chief instructor said.

Mr Rakov, 44, an "extremely experienced" instructor who had worked for the defence force for two decades, died at the scene in Goulburn.

It is believed Mr Rokov wrapped himself around the teenager to cushion him from impact.

The boy's parents were with him at the centre in Goulburn, before he was flown to hospital by helicopter.

He remains in a stable but critical condition at the Children's Hospital at Westmead, a spokeswoman said.

The boy's family has asked the Canberra Times not to name him at this stage.