From July 1, Australian supermarket shoppers get a new legal right: Coles and Woolworths will no longer be allowed to charge prices that are excessive when compared to their actual costs plus a reasonable margin. It sounds straightforward. But beneath the headline lie thorny questions about whether the law will deliver cheaper groceries or simply reshape how Australia's duopoly operates.
The Albanese government passed the ban as part of the mandatory Food and Grocery Code of Conduct, a response to years of complaints about grocery inflation outpacing broader cost-of-living pressures. For Australian households now spending an average of $204 per week on groceries, with meat prices up 3.9 per cent and coffee up 13.5 per cent in the 12 months to January 2026, the regulation arrives as a welcome symbolic intervention.
But the mechanism matters. The law targets only "very large retailers" with annual revenue exceeding $30 billion. Coles and Woolworths are the only two supermarket operators in Australia that qualify. This means Aldi, Costco, and other competitors face no equivalent restrictions. The ACCC, Australia's competition regulator, will enforce the rules through legal action, with potential penalties of $10 million per breach, three times the value of the benefit derived, or 10 per cent of annual turnover, whichever is largest.
The ACCC's chair, Gina Cass-Gottlieb, has put both chains on notice that enforcement is coming. "Whether it happens in the first year or it happens somewhat subsequent from it," she told media earlier this year, the regulator would be prepared to sue. The watchdog is already pursuing parallel legal action against both chains for allegedly engaging in misleading discount practices, raising prices on hundreds of products before placing them in promotional offers.
Coles and Woolworths have voiced strong opposition. Coles warned that the rules would place "upward, not downward" pressure on prices by limiting the promotional deals and loss-leader pricing that now anchor consumer behaviour. Woolworths called the regime "unprecedented" and claimed it created an unfair playing field. Both arguments contain uncomfortable truths. If the law prevents supermarkets from absorbing supplier cost increases through margin compression, prices will likely rise unless margins fall further.
The genuine complexity emerges here. The regulation requires companies to prove that prices reflect supply costs plus a "reasonable margin." But defining reasonable is the work of litigation, not legislation. Supermarkets will argue that high margins are necessary to fund service quality, product diversity, and logistics networks. Regulators will counter that global supermarket comparisons show Australian chains operate at world-leading profitability despite tight prices. Neither side is entirely wrong.
Economists and consumer groups remain cautiously sceptical. The regulation does not directly force prices down; it merely constrains how much profit supermarkets can extract from any given item. For that constraint to benefit shoppers, the ACCC must detect violations, prove them in court, and do so quickly enough that the deterrent effect translates into pricing behaviour. The latter two steps are uncertain. Supermarket pricing is dynamic and complex; proving that a specific price on a specific item is excessive requires reconstructing the entire supply chain for that item, including negotiated supplier costs that companies treat as confidential.
The ACCC has acknowledged that implementation will demand sophisticated monitoring systems, accurate supply chain data from multiple parties, and resources the regulator may not yet possess. Companies must keep pricing records and supply cost documentation for three years. Whether they will be forthcoming is another question. Supermarkets have every incentive to argue that costs are opaque, that suppliers demand confidentiality, or that comparing one store to another is methodologically fraught.
What the ban does offer with certainty is transparency and scrutiny. Coles and Woolworths will know that pricing decisions carry legal risk. ACCC enforcement action, win or lose, will publicise the chains' pricing practices and create political pressure. For some shoppers, that accountability itself may feel like a small victory after years of grocery inflation that outpaced wage growth and broader inflation.
For others, the law represents theatre rather than reform. The real issue, from this perspective, is market structure. As long as two companies control roughly two-thirds of Australian supermarket sales, they will face limited competitive pressure. Pricing rules that constrain margins may simply encourage both chains to adopt similar price strategies, maintaining duopoly returns at a new equilibrium. Aldi's growth, now challenging the incumbents, may do more to lower prices than any regulation.
The July 1 start date gives both the supermarkets and the ACCC four months to prepare. Expect announcements about compliance systems, calls for legal clarity, and political theatre from all sides. When enforcement begins, the real test starts. If the ACCC wins a early case and penalties sting, chains will adjust. If cases drag through courts and fines prove small relative to turnover, the law becomes a gesture.
For now, Australian shoppers have reason to watch closely but temper expectations. The regulation is meaningful; it formalises into law what was previously a political complaint. But it is not a structural fix. Expect some prices to fall, others to rise, and the duopoly to remain fundamentally unchanged. The law constrains excess without addressing the underlying concentration that enabled it.