Woolworths New Zealand was issued a warning by the Commerce Commission for what is a "likely breach" of the Grocery Industry Competition Act after the regulator identified and investigated instances where it considered Woolworths New Zealand was at risk of not meeting its obligations under the new Grocery Supply Code, according to a Thursday statement.

Woolworths updated its processes to meet its obligations, the regulator added.

However, only a court can decide if a breach had occurred.

The code places obligations on the major supermarkets regarding range reviews to decide which products are stocked. Woolworths, Foodstuffs North Island, and Foodstuffs South Island together have a 82% market share in the grocery sector in New Zealand.

"The risk of losing market access can lead to suppliers accepting conditions that aren't beneficial to them," Commerce Commission Head of Groceries Alice Hume said.