Live: Air New Zealand initially said all A320s would need to have a software update before they could fly again, but has now announced flights without the update will continue until 1pm Sunday.
Airbus said a recent incident involving an A320 family aircraft had revealed intense solar radiation could corrupt data critical to the functioning of flight controls.
The company has ordered an immediate change to a "significant number" of its best-selling A320 jets, which threatened to disrupt half the world's airlines.
Earlier, Air NZ chief safety and risk officer Nathan McGraw said, "as a precaution", all A320neo aircraft in its fleet would receive a software update, before operating their next passenger service.
However, he later revised the airline's position to say that, while 12 flights had already been cancelled, A320 flights would resume until just before 1pm Sunday.
An Air New Zealand Airbus A320 at Wellington Airport. Photo: AFP/ William West
"To allow aircraft to get to their destination and minimise disruption, a new update from the European Union Aviation Safety Authority (EASA) has advised that aircraft with this software can continue operating until 12:59pm on 30 November, New Zealand time. This means that, where possible, we are able to operate A320 services today, before commencing the required updates.
"Air New Zealand will begin rolling through the updates to its A320 fleet as quickly as possible to minimise ongoing disruptions.
"It is important for customers to know that this is a precautionary software update and does not present an immediate safety risk to our flights.
Jetstar also said some of its flights have been cancelled and it was working on how to get travellers moving again as quickly as possible, but did not say how many aircraft or flights were affected.
Passengers have been hastily trying to reschedule their travel at Auckland Airport. Photo: RNZ/Calvin Samuel
Airbus A320s were commonly used on Air NZ's Australia and Pacific Island routes.
In a statement, the plane manufacturer said: "Airbus acknowledges these recommendations will lead to operational disruptions to passengers and customers.
"We apologise for the inconvenience caused and will work closely with operators, while keeping safety as our number one and overriding priority."
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