A new whistleblower tool has been launched to help lift the lid on potential anti-competitive behaviour in the grocery sector.
The Commerce Commission said the online whistleblower tool used advanced data security and privacy.
The Commission said it would allow people to remain anonymous, removing the risk of retaliation if people came forward with information.
It offered a similar system for people to report alleged cartel conduct in the country.
Grocery Commissioner Pierre van Heerden said he was aware of situations where food suppliers were concerned about being disadvantaged if they shared information with the Commission.
"This is a sector that touches every New Zealander, so it's crucial that in conjunction with the obligations on the regulated supermarkets, we are aware of and can act on all potential issues for the long-term benefit of Kiwi consumers," he said.
The whistleblower tool can be accessed on the Commerce Commission's website.
The Commission said it used the WhistleB system, owned by US firm Navex.
The tool provided a secure channel where users could report information without disclosing personal information.
Reports would be received by "specifically trained" Commerce Commission staff, and the data would be held securely in encrypted cloud-based storage.
"The major supermarkets have confirmed that should any suppliers want to come forward to the Commission and report issues, this would not breach any obligations they have with the supermarkets."
The Commission urged people who wished to complain to "take care" when providing details, so they would not inadvertently disclose their identity.