Flights into Queenstown Airport are being cancelled tonight, after air control staff called in sick.
About six flights that were due to fly into Queenstown Airport after 7.30pm have been rescheduled.
A statement from Airways said airlines were making other arrangements for customers on those flights.
Queenstown air traffic control would resume just after 6am tomorrow.
"If you are scheduled to fly in or out of Queenstown from 7.30pm this evening, please contact your airline for instructions," it said.