A father wanting to get his daughter home for Christmas is upset that his daughter's flights from and to the United States have been cancelled by Air New Zealand.

Air New Zealand is cancelling and rescheduling about 1.5 per cent of its flights during the next six months in what it says is a proactive move to avoid cancelling services closer to the time that passengers have booked to travel.

About 100,000 passengers are being affected, and are in the process of being contacted by the airline.

David Brown, who booked a flight to NZ from the US for his 19-year-old daughter on December 14, said he was put on hold for over five hours when he called Air NZ's call centre on Saturday afternoon after receiving an email that her flight had been cancelled.

When he enquired further, Brown was shocked to find out that his daughter's flight back to the US on January had also been cancelled.

The airline offered Brown alternative flights for his daughter - a day earlier on December 13, two days later on December 16 or on the same day as the original booking but on a route that would take 20 hours instead of 15 hours of flight time.

But Brown said none of them were suitable.

"The alternative routing would have had our daughter travel for nearly 24 hours to get back to NZ from the US," he said.

"She couldn't do the day before because she had university exams, and the flight on the 16th would mean she'll miss her medical appointments."

When he pointed out there was a direct flight from Chicago, Brown said the airline refused to put his daughter on that flight and charged him an extra $1000 to put her on that flight.

"They refused to allow us to pay this extra charge using Airpoints and we had to pay by credit card," Brown said.

"But the really alarming matter was that when I checked on her flight back to the US on January 3, they confirmed that this too had been cancelled.

"When I asked why we had not been advised, they stated that they will be advising passengers for the flights in January and beyond at a later date even though they have already cancelled them from their schedule."

Brown said Air New Zealand should have had "the courtesy and respect" to advise customers of all flight changes so that they can make alternative plans during the peak holiday season.

His daughter, who is studying at a university near Detroit in Michigan, was booked to fly back on Air NZ's Houston-Auckland direct flight which would take 14 hours 55 mins.

"We were advised via email that they shifted her to the same flight the previous day however this is not possible as she has a university exam that previous day," Brown said.

"After waiting on hold for a full five hours, they offered us a Houston-LA-Auckland flight with a journey time of 20.5 hours.

"If she had to fly Detroit-Houston-LA-Auckland it would take her nearly 29 hours to get home which would simply not be a practical option - and through no fault of our own."

His request to put her on the direct flight from Chicago would cost an extra $1035, which he paid. Air NZ is refunding Brown after enquiries by the Herald.

Brown said he was shocked when he checked his daughter's Auckland-Chicago flight back to the US on January 3 only to find that it had been cancelled too.

"We asked the call taker why was it that we had not been advised, and we were told that they were not advising people for those flights in January yet," he said.

"We have been loyal customers of Air NZ and to hear that they had cancelled flights and were knowingly withholding that information from customers left us feeling badly let down by the airline."

Brown said cancelling flights increases scarcity which in turn increases price and by not giving customers as much notice as possible "simply hits people in the pocket".

An Air New Zealand spokeswoman said its customer team was working around the clock to action the scheduled changes for the next six months, and these could take a few days due to the number of impacted passengers.

"We are incredibly thankful for the patience our customers are showing us through this disruptive period," she said.

"We understand how frustrating it is for those whose flights are adjusted and we do our best to work with them to find a reasonable solution.

"In this instance, where we have been unable to provide a new flight option that is suitable for the customer, a refund has been given."

The spokeswoman added that Airpoints could only be used for new bookings and not to adjusting flights.