The Commerce Commission has issued a draft framework for open disclosure of profits by airport companies to curb the risk of price-gouging.
Last year Parliament amended the Commerce Act so that airport companies - and gas pipeline and electricity lines companies - came under Commerce Commission scrutiny.
However, airlines say the proposals do not go far enough.
The Board of Airline Representatives says the Commission has turned a blind eye to the capital gains airports have made on their assets in the last seven years. Executive director John Beckett says these will not be counted as profit.
However, the commission says the guidelines are still in draft form and there will be more consultation before the final framework is decided.