A dispute over the growing abuse by consumers of manufacturer coupons may end up in the courts after supermarkets were accused of having policies that were "no different from allowing consumers to shoplift".

The Institute of Sales Promotion, which represents manufacturers that issue money-off coupons, said it was taking legal advice because one in six of the 450 million money-off coupons distributed in the UK each year was redeemed against the wrong product, and the problem was costing fmcg companies £50m a year.

The ISP said it was consulting solicitors on whether it could force retailers to only accept coupons redeemed against the manufacturer's product. One fmcg supplier said consumer advice websites such as moneysavingexpert.com had spread the word that supermarkets often accepted coupons as cash.

He said the onset of recession had coincided with a new wave of deliberate attempts by organised coupon fraudsters to scam manufacturers. Tesco last year sent him a bill for spent coupons, £9,000 of which was for random face value sums never issued, he said.

"We issue 20p coupons but we had some coming back with the value of £24.31, another one £1.17. I realised the barcodes had been manipulated [by organised gangs]." Tesco agreed to refund the money after he disputed the claim.

Peter Kerr, chairman of the ISP's coupon committee and MD of coupon-handling company MRM, said he had recently dealt with 15 cases where individual stores had tried to claim back a higher value of coupons than the total value of product sales. "The situation is dreadful for some manufacturers," said Kerr. "Tens of thousands of pounds have been at stake at individual stores."

Tesco said it allowed cashiers to accept "single coupons but not multiples" without checking if the item had been purchased because it was not practical to spend time checking.