The Commerce Commission is filing criminal charges against Woolworths and two Pak'nSave supermarkets for inaccurate pricing and misleading specials.

The charges will be made separately against Woolworths, Pak'nSave Silverdale and Pak'nSave Mill Street.

The commission said there are ongoing issues with pricing in the supermarket sector and the operators may have breached the Fair Trading Act.

In a statement, deputy chair Anne Callinan said operators should know what the expectations are.

"Supermarkets have long been on notice about the importance of accurate and clear pricing and specials, and we're not satisfied with the continuing issues we're seeing across the industry.

"Pricing accuracy is a consumer right and an expectation of a competitive market. The major supermarkets are large, well-resourced businesses that should invest the time and effort to get pricing and promotions right."

She said the charges were filed to remind all supermarkets that they are expected to fix the pricing accuracy issues and implement better processes.

The Commission said it has ongoing investigations into other supermarket operators.

Grocery Commissioner Pierre van Heerden said the introduction of a mandatory disclosure standard would make it easier to identify problems so they can be remedied.

"The standard will require the major supermarkets to regularly disclose information about customer complaints, including around pricing and promotional issues.

"The major supermarkets don't have consistent processes for recording customer complaints - the lack of clarity and reporting means supermarkets can't identify potential compliance issues within their businesses. This impacts consumers as their complaints may not be being dealt with effectively, which we would expect in a competitive market."

The commission is working on the standard with he major supermarkets and expects to have a draft published in the new year.