Civil Aviation is investigating an incident in which a helicopter was damaged west of Lake Wanaka, near Minnaret Peaks, about 1pm on Thursday.
CAA communications manager Mike Richards said yesterday there was no-one in the helicopter and no-one was injured.
Pilot Timothy Hutchison had left the the idling helicopter, Mr Richards said.
"The rotor blades were seen to begin oscillating, striking the tail boom and the ground beside the helicopter."
A CAA investigator would be assigned to the case early this week, he said.
The Squirrel helicopter belongs to Alpine Helicopters, which is owned and operated by the Wallis family.
The incident happened at the same time as the World Heli-ski Challenge but was not connected with that event.
It was carrying passengers on a private charter, Jonathon Wallis said last night.
It received only minor damage and was able to be flown out on Friday.
