The commission said that as a result of its investigation, the Poultry Industry Association of New Zealand (PIANZ) had reviewed labelling standards for fresh whole chickens and changed its approach to sizing.
PIANZ executive director Michael Brooks said the inquiry had led to an industry-led review about how companies reflect weight on packaging.
As a result, the industry "has been working collaboratively both with the Commerce Commission and all poultry companies to communicate this more effectively".
"The Net Weight measurement was a solution that satisfied all parties and we have been working with the major poultry companies to ensure all packaging reflects this."
The commission confirmed that Tegel and Inghams had co-operated in resolving the issues raised, and it accepted that changes had been made to packaging of stuffed and marinated chickens.
Packaging now showed the net weight of the chicken including stuffing and marinade and will no longer feature a size. Consumers may still see existing packaging on the shelves due to the time required for introducing new packaging.
The commission has issued letters of warning to both companies but said it would not be taking further action at this time.
Tegel and Inghams have been sought for comment.