Otago Regional Rescue Trust chief pilot Graeme Gale said conditions were cold and wet with low cloud and reduced visibility during the rescue flight.
The reduced visibility was "something you need to be careful to work with", Mr Gale said.
St John South Island communications adviser Gerard Campbell said a paramedic on the helicopter from Dunedin had treated the injured man before the helicopter left the Maitland Hut area shortly after 1pm.
Police were alerted by St John at 11.10am and the helicopter reached the hut about 12.30pm, a police spokeswoman said.
It is understood the man was not seriously injured but could not return without help.
The four-bunk Maitland Hut is at an altitude of 960m, in the Ruataniwha Conservation Park, and is also near Twizel.
The hut is 10km from Lake Ohau Rd, and can be reached by a 20.8km track which is assessed as difficult, requiring tramping experience, according to the Department of Conservation internet site.
