Aircraft departures across New Zealand were briefly halted Monday after problems with the nation’s air traffic control system. Air navigation provider Airways New Zealand said the failure of one of two uninterrupted power supplies prompted its radar and communications system to revert to back-up mode. The problem was identified about 1:20 pm local time when a fire alarm was activated by smoke from the power supply. READ: Airports call for supersonic standards and practices. “While Airways was able to continue to safely manage domestic airborne traffic, as the system was in back-up mode a conservative approach to managing New Zealand’s airspace was taken, which included halting departures within New Zealand airspace,’’ the air traffic controller said in a statement. “Our airborne international flights were unaffected as our main Oceanic control center is independently managed from Auckland.“ Airways said it had identified the problem by 2 pm and by 2:15 pm operations were running normally and domestic flights were departing again.  Almost 40 flights were affected. It said the failure occurred at a significant time of day when traffic flow was increasing because of arriving international flights. The departures were halted while the arrivals were being managed, it said.