Air traffic control provider Airways says a near mid-air collision in August last year does not mean there are serious problems with its system.
The Transport Accident Investigation Commission says mistakes by air traffic controllers put a skydive plane and an Air New Zealand flight on a collision course, south of Auckland.
The skydive aircraft, which had just dropped four parachutists, came within 400 feet, or 122 metres, of an Air New Zealand Bombardier aircraft over Mercer.
The airliner eventually detected the potential collision and diverted.
The commission has made five recommendations to the Civil Aviation Authority to address safety, including auditing Airways' operations.
Airways chief executive Ashley Smout says lessons have been learned and procedures changed.
"It happened on our watch, it shouldn't have happened, but we've immediately acted to put a whole range of new process and procedures in place to reduce the risk of it happening again."
Mr Smout says the company's systems are at, or close to, the world's best, when measured against the most advanced air traffic management companies in the world.
"I can assure the flying public that it's one of the safest air traffic management systems in the world."
The commission's report says both aircraft had been cleared by traffic controllers.
It says the controller did not fully examine the route the airliner would take when he cleared its destination.
Furthermore, the two-member control team missed an automated collision warning in the control centre.
It says the low level of supervision of controllers could have caused unsatisfactory work habits to develop which may have led to the incident.