Foodstuffs has pushed back hard against suggestions it should be broken up, releasing a review it commissioned that takes aim at the split model. The grocery cooperative runs the New World, PAK'nSAVE and Four Square banners and is one of two companies that dominate supermarket sales across New Zealand. Regulators and ministers have been weighing whether forcing retailers to separate their wholesale and retail arms would loosen that grip and bring prices down. The Foodstuffs-commissioned review argues that kind of restructuring would not deliver the competition gains its backers expect. It points to the cost and disruption a split would create, questioning whether shoppers would see any benefit at the checkout. Executives have used the findings to argue that voluntary steps are the better path forward. Critics are unlikely to be swayed, since the review was funded by the very business it defends. Debate over the supermarket sector is expected to continue as the government decides what action to take.