A $3 million expansion of an air traffic surveillance system throughout Otago and Southland is almost complete.
Airways New Zealand has spent the past 18 months planning and installing nine new air traffic surveillance stations in remote mountain locations in the regions.
Head of engineering and maintenance Peter O'Regan said the technology would be ''flight tested'' in the next few weeks and become fully operational towards the end of the year.
In 2009 and 2010, Airways established 14 air traffic surveillance sites around Queenstown.
The nine new sites expanded the network, providing air traffic controllers with a digital map of aircraft locations. They therefore did not need to rely on verbal position reports, Mr O'Regan said.
''The information to the controller will be a lot more accurate, which means more aircraft can be directed into certain air spaces, which improves efficiency of the whole network,'' he said.
Airways paid for the surveillance system, and had agreements with airlines.
Overall safety improvement was the driving force behind the technology installation.
Mr O'Regan said the geography of Otago and Southland was complex and the new system would reach where radar surveillance did not.
Installing the equipment had been challenging, but was worth the effort, he said.
''The guys have been working in some really remote spots, using helicopters to fly heavy gear to mountain tops with high exposure to wind, rain and snow.
"At Wether Range, near Omarama, for instance, we drove a digger to the peak to dig the foundations, and then used a helicopter to fly in the 13 tonnes of concrete needed for the station foundations.''
Other station sites were High Peak, Mt Prospect, Kuriwao, Bald Hill, Mt Stuart, Mt Cargill, Mt Studholme and Mt Mary.
