Air New Zealand chief executive Rob Fyfe says the Australian competition watchdog's draft determination to block an alliance with Virgin Blue Holdings Ltd would threaten the airline's future.

"If we are to earn the right to continue to fly and grow, then the deal with Virgin Blue is a central plank of that strategy," Fyfe said at a National Aviation Press Club lunch in Sydney yesterday.

"Obviously the ACCC's [Australian Competition and Consumer Commission] preliminary finding represents a threat to this strategy, in effect, a threat to our future."

Virgin Blue and Air New Zealand hope to form an alliance on transtasman services that would see the two carriers collaborate on pricing, revenue management, schedules, capacity and routes.