The woman was initially taken to Frankton's Lakes District Hospital after the incident, which happened at the Ashenhurst Way house, in the suburb of Shotover Country, about 1pm.
A police statement said the woman was later flown to Dunedin by an Otago Regional Rescue Helicopter in a moderate condition.
A neighbour, Michelle Carpenter, said she had been in her living room with an outside door slightly open when she heard a ``thump''.
She assumed the sound had come from a nearby building site.
``My instinctive feeling was that someone had fallen or something was dropped.
``There were no other sounds; no shouting or crying - I didn't think anything of it.''
She was surprised to see police cars in the street a short time later.
``I went out and saw a gentleman holding his head in his hands.''
Sergeant Keith Newell, of Queenstown, said the woman's injuries were caused by the ``accidental discharge'' of a firearm.
An investigation was under way.
