The commission said Christchurch International Airport's proposed prices over the next two decades were significantly higher than its view of what was acceptable, and tougher disclosure requirements had little impact on promoting price efficiency.
The airport was targeting a return of 8.9% over the next 20 years, well above the commission's view of an acceptable return of between 6.6% and 7.6%, the regulator said in its draft report on the hub's information disclosure.
Mr Rooney said his assessment of the regulatory risk in the airport sector rose slightly following the commission's draft report.
Christchurch airport had set lower prices in the next five years which were not considered as targeting excessive profits, though that appeared to have been driven by the drop in demand after the region's spate of earthquakes rather than the rules governing disclosure.
The section 5G review process on each of New Zealand's major airports had resulted in mixed outcomes.
Wellington was deemed to be generating excessive profits and had subsequently outlined its intention to reconsult with the airlines.
The commission determined Wellington would generate an internal rate of return of 12.3% for the current pricing period.
In contrast, Auckland International Airport was not judged to be earning excessive profits with a 7.9% return, Mr Rooney said.
