What grocery competition policy means for price tracking

RNZ reports that the Green Party is proposing to break up New Zealand's supermarket duopoly and establish a publicly owned grocery retailer, KiwiMart.

It is a policy proposal, not a change at the checkout today. But it raises a useful question for shoppers: if the shape of the grocery market changes, what would success actually look like in the prices we pay?

Two different routes to more competition

The KiwiMart proposal is one route: change the market structure and add a public retailer. Its effect would depend on details still to be worked through, including the stores, supply arrangements, product range and pricing model.

The Government is pursuing a different route, centred on making entry and expansion easier. Its 2025 request for information asked prospective entrants and investors what they would need to compete at a national scale. Officials were asked to seek responses from existing local operators such as Costco and The Warehouse, and overseas firms including Coles, Aldi and Lidl.

Since then, the programme has included faster pathways for new supermarket developments and guidance for overseas grocery investors navigating the Overseas Investment Act. That guidance is intended to give applicants more certainty; it is not an announcement that a new international chain is opening in New Zealand.

These approaches have different trade-offs and political arguments. The useful common ground is simpler: both are trying to create more choice and stronger pressure on grocery prices.

The baseline matters

The Commerce Commission's latest annual report says the major supermarkets still held more than 80% of the national retail grocery market over the period it examined. It also found retail prices increased, while noting that regulatory changes were making it easier for smaller and alternative retailers to enter or expand. Read the Commission's summary.

That is the national picture. A shopper's experience is more local.

Kete records prices every day at individual Woolworths, New World and PAK'nSAVE stores — and for Woolworths, at delivery-suburb level. That matters because a price is not always the same across an island, or even within a chain. A new competitor in one region may affect the nearby stores first, while another area sees no immediate change.

What we can measure — and what we cannot

Price tracking cannot tell us whether one grocery policy is better than another. It cannot measure store-build costs, supply agreements, employment effects or whether a proposal is workable.

It can provide a transparent record of outcomes shoppers can see:

• Whether the shelf price of the same product changes over time.
• Whether specials become deeper, more frequent, or simply follow a higher regular price.
• Whether price gaps between nearby stores or chains narrow or widen.
• Whether a new retailer adds meaningful choice in places where it opens.

Those comparisons need care. Prices move for many reasons: seasonal supply, exchange rates, supplier costs, promotions and product changes can all matter. A single cheap item or a short-term special is not proof that market competition has changed.

Watch the evidence, not just the announcement

Whether the next major change comes from public ownership, an overseas entrant, independent retailers, or the existing chains responding to pressure, the test for shoppers is sustained and local: are comparable baskets becoming more affordable, and is there more genuine choice where people live?

Kete is built to make one part of that test easier. Search for a product, choose the stores relevant to you, and look at its history. Policy announcements set a direction; the price record shows what reaches the shelf.