There were 40 passengers on board who disembarked on the runway after the plane landed at Wellington.
The pilot declared a mayday and was able to safely land following an engine problems.
Aviation commentator Irene King told RNZ's Morning Report she doesn't believe it was an engine fire.
"These engines will flame but that's just part of, in this case the shut down."
She said pilots were trained to cope with such situations and planes have two engines but could fly on one.
"The issue is why, and that's more critical, why did it happen."
Investigators from the Transport Accident Investigation Commission, and Air New Zealand itself, would be working on that, King said.
"There'll be some urgency to understand why so all of their focus will be on the why... They'll be scratching their heads about why, as we all are."
'Flying no less safe'
New Zealand Airline Pilots' Association president Captain Andrew McKeen said the outcome on Sunday was what he would have expected.
"It was serious, but it was never not a safe situation to be in," he told Morning Report.
McKeen acknowledged it would have been a scary time for the passengers.
"It looked quite spectacular with all the smoke behind the aircraft, but this is something that pilots train for and something that aircraft are designed to contain.
"Off the back of it I would say that flying is no less safe because of it."
There was no known problem with the type of aircraft and they were flown around the world, McKeen said.
