Air New Zealand and Qantas have banned men from sitting next to unaccompanied children on flights, sparking accusations of discrimination.

The airlines have come under fire for the policy that critics say is political correctness gone mad after a man revealed he was ordered to change seats during a Qantas flight because he was sitting next to a young boy travelling alone.

Auckland man Mark Worsley says an air steward approached him after take-off on the Christchurch to Auckland flight and told him to change seats with a women sitting two rows in front. The steward said it was the airline's policy that only women were allowed to sit next to unaccompanied children.

"At the time I was so gobsmacked that I moved. I was so embarrassed and just stewed on it for the entire flight."

The 37-year-old shipping manager, who has 2-year-old twins, followed the incident up with the airline and was told Qantas wanted to err on the side of caution.

"I felt that it was totally discriminatory. Besides the point of what the hell was I going to do on a crowded flight."

The incident, which happened a year ago, irked Mr Worsley so much that he recently contacted National Party political correctness eradicator Wayne Mapp.

Dr Mapp told the Herald the airlines' policy was an example of political correctness that had got out of hand.

"I think this is a gross over-reaction by the airlines. What do they think men are going to do that women won't? It is the same as saying men shouldn't sit beside children on a bus."

A Qantas spokesman confirmed the Australian airline, which operates domestic flights in New Zealand, does not allow unaccompanied children to sit next to men. The spokesman said the airline believed it was what customers wanted.

Air New Zealand spokeswoman Rosie Paul said the airline had a similar policy to that of Qantas'.

"Airlines are temporary guardians of unaccompanied minors so we have preferred seating for them."

Ms Paul said Air New Zealand tried to seat children near a crew area so crew could keep an eye on them and, when possible, children were seated next to an empty seat.

"Sometimes this isn't possible, so the preference is to seat a female passenger next door to an unaccompanied minor."

When the Herald asked her if the airline considered male passengers to be dangerous to children, Ms Paul replied: "That's not what I said."

When it was put to her that that was the implication of the policy, she repeated: "No, that's not what I said."

Children's Commissioner Cindy Kiro said she commended the airlines for putting thought into the policy and for endeavouring to keep children safe.

Dr Kiro said she did not think it was intended to be a slur against men.

- Additional reporting: Kevin Taylor