The native mountain parrot should eat such things as native berries, seeds, insects including giant weta, roots and spaniard grass shoots.
Van Klink said female kea would begin nesting soon, and the male would deliver her food.
''So he'll be taking back potentially junk food from the skifield.''
He urged skiers to secure bags containing food and remove left-over food from tables to stop kea helping themselves.
The Department of Conservation (DoC) is also concerned about kea being fed.
Queenstown ranger Chris Hankin said yesterday people feeding kea ''is definitely contributing to the kea's decline''.
''While a single chip or piece of bread is unlikely to be harmful, people must realise that if a kea is continually fed human food then the bird develops an artificial and unhealthy diet that replaces much of the natural food it needs.
''This can easily result in premature death.''
Hankin said there can be further difficulties when a kea is supporting chicks.
''If an adult has an unhealthy artificial diet so will their chicks, as they rely on regurgitated food from their parents.''
''DoC urges everyone to speak up if they see people feeding a kea.
''Chances are that person simply has no idea and will thank you for the advice,'' Hankin said.
DoC manager Jackie van der Voort said yesterday she believed there were more birds at the ski area this year than in previous years.
The field worked with the trust and DoC, she said, and signs advising skiers not to feed kea were in place.
Staff were advised about the kea issue at the start of each season.
Van Klink said Treble Cone staff had improved the situation by putting a heavy cover over the dumpster at the cafe to keep kea out of the rubbish.