The Department of Conservation (DOC) has apologised for granting a concession to a private company to take more walkers on the Routeburn Track.
Dunedin climber Chas Tanner laid a complaint with the Office of the Ombudsman and argued the concession contravened the Conservation Act.
In June 2013, Mr Tanner complained about the decision to allow the private company Routeburn Walks Limited to increase the number of its guided walkers from 24 to 40.
The Office of the Ombudsman upheld the complaint, saying it flew in the face of the limits set in the new Mount Aspiring Plan.
In its opinion, released in December, the office said the decision to approve the increase in walkers made a "mockery" of the public consultation process in the development of the plan.
DOC said it would develop new guidelines for handling applications for commercial concessions in national parks, and has apologised to Mr Tanner for the frustration he experienced.