Consumer advocacy group Choice has wildly overstated the difference in prices between the big supermarkets and discount retailer Aldi, analysis by a Wall Street investment bank has found, while Woolworths and Coles described the taxpayer-funded research as inaccurate and not useful.

JPMorgan’s price check of some 100 home brand products across the big supermarket groups found the difference between Woolworths and Coles, and Aldi, was 8 per cent and 9 per cent respectively, well below the figures published by Choice in a survey commissioned by the federal government.