Passengers flying in to the capital are being stung $5 more in landing charges than in Auckland, airlines say.

Yesterday the Commerce Commission published its first report into landing charges, concluding that the current light touch regulations were allowing Wellington Airport to "extract excessive profits".

Wellington Airport is jointly owned by Wellington City Council and infrastructure investor Infratil.

The commission said the airport's profit targets between 2013 and 2017 amounted to overcharging of at least $21 million, and up to $39m, after the airport opted not to use the commission's formula for calculating charges.

"We believe that definitely, Wellington Airport is charging too much," commission deputy chairwoman Sue Begg said.

The commission has no power to influence landing charges, with the current regime simply requiring airports to disclose detailed financial reports and forecasts.

Ms Begg said the commission could not recommend it be given greater powers over airports.

However, she said the report, due to be passed to the transport and commerce ministers before Christmas, could be "like a first step, I suppose" towards price regulation.

Airlines have long complained that airport landing charges are unreasonable, with Air New Zealand claiming earlier this year that Wellington's pricing structure would overcharge the industry by $100m by 2017.

John Beckett, spokesman for the Board of Airline Representatives (BARNZ), claimed that Wellington's charges for domestic flights amounted to $10.39 per passenger - compared to $5.55 at Auckland Airport.

"The cost to the airline for domestic passengers is virtually twice that of Auckland," Mr Beckett said, adding that airlines' thin profit margins meant the costs would be faced by consumers.

"All of these increases in charges do come through to the travelling public, or in higher charges for freight."

Wellington Airport chief executive Steve Sanderson said BARNZ's use of the figures was "mischievous" because the airport had moved to a model where there was less difference between domestic charges and international charges.

Mr Sanderson said the commission had failed to recognise concessions it offered to airlines, designed in part to encourage expansion.

Taking the concessions into account would reduce the effective rate of return of the airport from 9.5 per cent to 8.1 per cent which was "within the realms of what the commission finds acceptable" and meant it was not worthwhile placing more onerous regulations on the industry.

- © Fairfax NZ News