A Queenstown youth wrote the threatening note that caused a bomb scare at the resort's airport last month.
The note was found on board a Qantas flight from Sydney by a cleaner after it landed at the airport at 2.14pm on July 24.
After flight crew raised the alarm, an evacuation of the airport terminal began about 3.20pm to allow Aviation Security and dog teams to search the building and the Boeing 737-800.
The scare caused disruption for hundreds of passengers and led to the diversion of two incoming domestic flights and the cancellation of three outbound flights, including an international flight to Sydney.
A media statement from police yesterday said they were disappointed the actions of one person had tied up emergency resources that could have been needed for other serious situations.
Detective Matt Jones, the officer in charge of the investigation, said the youth had been referred to Youth Aid.
Police have refused to answer questions about why it took more than an hour to begin the evacuation of the terminal.
The airport's chief executive, Colin Keel, said in the statement he was pleased the source of the threat had been identified.
``The safety and security of our visitors and airport and that of our local communities always come first,'' Mr Keel said.
The airport's communications manager, Jen Andrews, said it would not be making any further comment as justice proceedings were under way.
Qantas Airways senior manager of corporate communications Stephen Moynihan said the company thanked police for pursuing the matter.