About 20 Air New Zealand domestic routes were abandoned yesterday, as airlines tried to clear a backlog of passengers affected by the Airways New Zealand air traffic control radar fault.
Airways was unable to reveal how many flights were affected by the fault caused by an "internal network outage" - including some on airport tarmacs with passengers on board.
However, 160 Air New Zealand and seven Jetstar flights were affected when all outbound flights were immediately ceased at 2.41pm.
Today Airway's chief operating officer Pauline Lamb told Radio New Zealand she apologised to the travelling public that were disturbed as a result of the incident, which she called "undesirable".
"But because we do have fall back procedures in place which the pilots know about, which the controllers know about, we are able to handle the situation safely, and that is indeed what we did yesterday.
"Our pilots and our controllers handled it very professionally."
Ms Lamb confirmed it was a internal network outage caused the problem.
"We normally have route data around the country providing information to controllers to enable them to do their job. In this case, the radar data and the communications data that's normally fed to them was not distributed how it should be.
"It was due to three events happening at the same time, we isolated those events as soon as we were able to verify the integrity of the system we were able to get it up.
"Although we isolated the event and are very sure the system integrity is sound at the moment, and will remain so, we want to investigate thoroughly to eradicate a chance of this type of system failure."
Meanwhile, the Transport Accident Investigation Commission says it will launch its own investigation into the incident.
It said it expected the inquiry to take 18 months, although it had the ability to issue safety recommendations at any time, should the need arise.
A spokesman said the purpose of the inquiry would be to identify the circumstances and causes of the incident, to help reduce the possibility of a recurrence.
He said a team of three investigators had began gathering initial evidence, and they were working alongside the Airways Corporation and Civil Aviation Authority.
The Civil Aviation Authority also confirmed it would be launching its own investigation into the incident.
A spokesman said a safety investigation would be launched, focusing on identifying the cause or causes of the incident, while working on a solution to prevent it from happening again.
He said the Civil Aviation Authority was unable to comment further, until the investigation was over.
