Eight passengers had to be bumped from a flight packed with students because the plane was too heavy.
A passenger on board the flight from Wellington to Dunedin on Saturday accused Air New Zealand of being "pretty incompetent".
The passenger believed the issue came up because the airline sold too much excessive baggage.
Michael Reddell was on the plane to Dunedin to take his daughter to the University of Otago when the airline announced passengers would need to disembark or the baggage be unloaded.
While Reddell and his family were able to get on another flight to Dunedin, via Christchurch, about eight hours later - with all three suitcases in tow - his daughter was disappointed to miss out on the first day at her hall.
Passengers were told the aircraft was overweight by 1300 kilograms, Reddell said.
The majority of the University of Otago's halls of residence, or residential colleges, opened on Saturday.
Reddell took up an offer from Air New Zealand of a $400 voucher - which he said had to be increased to $700 to tempt enough volunteers to disembark.
But Reddell said he expected more from a "high-performing, well-functioning airline" like Air New Zealand.
"This is one of those flights when there are students going down with staggering amounts of luggage," he added.
"For an entirely predictable event - people moving into halls in Otago - it just wasn't very well done."
Air New Zealand Chief Operating Officer Alex Marren said in a statement it was not a baggage issue and instead down to the plane having too much fuel.
"On Saturday, our team managing NZ681 from Wellington to Dunedin had to make weight and balance adjustments to ensure the safe operation of the flight. The aircraft was over-fuelled, which meant the total payload exceeded the safe operating limit.
"While this is a rare occurrence, it meant we needed to seek volunteers willing to be rebooked on a later service.
"Eight customers were rebooked on the next available service and were compensated as an apology for the inconvenience caused.
"We’d like to thank them for their patience and understanding as we worked through this."
He said customers can check in up to three excess bags at the airport, and the airline's teams accounted for this within the aircraft's maximum allowable weight.
"With the influx of university students traveling to Dunedin, we planned for increased baggage and passenger demand, adding 36 extra flights in and out of the city over the weekend. In this instance, while excess baggage was accounted for, the over-fuelling meant the flight could not safely operate at its planned weight, requiring adjustments before departure."
Consumer New Zealand said it would expect Air New Zealand to comply with its domestic flight disruption policy.
"This requires the airline to rebook any affected passengers on the next available service, cover any additional costs (such as accommodation, transfers, meals ) and also provide compensation of between $100 and $300 per passenger, depending on the length of the delay."
