While major supermarkets in New Zealand maintained their national market share of 82%, Woolworths Group (ASX:WOW) saw a continued decline in market share over the past five years, with its national market share dropping to 27% from 30% between 2019 and 2024, New Zealand's Commerce Commission said in the annual grocery report on Wednesday.

The report monitors key measures of competition in New Zealand's grocery sector. Average gross retail margins slowed after four years of material increases in 2024.

For non-fresh products, average gross retail margins declined slightly in 2024 across Woolworths/Countdown stores across the country.

Access to Woolworths stores is the greatest in the country, with 78% of the country's population having a store within 10 minutes.

The regulator noted that the information used to compile this report was supplied via information requests to Foodstuffs North Island, Foodstuffs South Island, Woolworths New Zealand, and The Warehouse.

The majority of the new regulated grocery retailer stores were opened in the North Island between July 2023 and November 2024, the report noted. The top of the South Island, West Coast, Otago, Waikato, and Taranaki are regions where the major grocery retailers continued to have the most dominance.