Night flights to tourism gateway become possible as aviation officials give safety clearance.
Airlines have welcomed the prospect of flying into Queenstown after dark now the resort's airport has safety clearance for night flights.
Pilots say a new range of safety measures that would have to be implemented would improve safety at what is a "challenging airport".
The airport is allowed flights until 10pm, but evening flights could occur only in summer as aircraft were restricted to flying in daylight hours.
Air NZ's David Morgan welcomes night flights.
Queenstown Airport and tourism authorities say the possibility of extended operating hours could boost visitor numbers during the winter peak when the window for using the airport is at its narrowest.
Airlines are now assessing the commercial case, and if they commit to after-dark flying the airport will have to spend up to $10 million on lighting and widening the runway.
Queenstown Airport Corporation chief executive Scott Paterson said the decision by the Civil Aviation Authority and Australian Civil Aviation Safety Authority was a "potential game-changer" for Queenstown.
He said advanced navigation technology now in use in Queenstown was the key to enabling night flying.
The CAA's general manager for air transport and airworthiness, Stephen Hunt, said the approval process had taken two years to work through.
Sixty-six safety changes would be made, the most important being extra lighting and widening the runway from 30m to 45m.
"At night you don't have visual cues, so the crux is a lighting package with adequate cues and references."
The lighting changes would include a short set of lights leading into the runway, a line of lights down the centre, lights on the side of the approach end to give indications of whether the approach angle was correct and lights marking the latest point at which an aircraft could touch down.
"These are really significant changes but the biggest change will be the widening of the runway," said Hunt.
Satellite navigation in the area enabled aircraft to weave their way around mountains with a high degree of accuracy.
"The CAA doesn't rank airports' difficulty, what we do is look at is the complexity to fly in there and the aggregate of the risk," he said.
"In Queenstown there is terrain and wind issues but those are present in many airfields."
Air New Zealand chief flight operations and safety officer David Morgan said the green light was a welcome development.
"It's now up to each airline to consider the viability of operating outside of daylight hours at Queenstown and we will do that in due course as the airport company progresses the infrastructure upgrades."
Qantas Regional's general manager for New Zealand and Pacific Islands, Igor Kwiatkowski, said allowing after-dark flights would give greater flexibility to its Queenstown flying.
The airline would now assess the need for evening flights from a commercial and operational perspective.
Subsidiary Jetstar, which flies domestic and transtasman flights into Queenstown, said flight time flexibility was important to Jetstar and the approval by the CAA and its Australian counterpart was an important first step. It, too, would assess the case for evening flights.
Paterson said the airport had a clear idea of the technology, infrastructure and operational steps required but evening flights wouldn't be introduced before winter 2016.
"Winter is our peak and they [flights] have to be squeezed into a very small window, particularly the transtasman ones given the time difference with Australia.
"When they arrive in Queenstown in the mid-afternoon they are scrambling to turn that plane around and get out again," he said.
"For leisure travellers it would make weekend holidays from Auckland and Australia possible year-round. It would also give business people more flexibility with their travel plans and allow people to base themselves in Queenstown and commute to other main centres for work."
The New Zealand Airline Pilots Association said Queenstown's location and changeable weather made it challenging and the associated package of safety improvements was welcomed.
Once implemented these would improve safety at what was one of New Zealand's most challenging airports for pilots in terms of airline operations, because of its geographic location and changeable weather.
Before after-dark flights can start:
• Airlines must assess the operational and commercial case.
• Airport runway will have to be widened from 30m to 45m.
• Comprehensive aeronautical lighting must be installed.
• Customised crew selection and training will be needed.
• Full capability of navigation technology must be used.
• On-board flight procedures will change to reduce pilot workload on final approach.
• Individual airline will have to apply for night-flight approval.