Changes to the age discrimination laws next month have thrown the structure of the minimum wage and employers' legal standpoint into doubt, claims the British Retail Consortium and other leading experts.

The new regulation means that unless companies strictly adhere to the national minimum wage banding of 16 to 17-year-olds, 18 to 21s, and 22s and over, then they could be open to legal action.

Rachel Krys, head of communications at the Employers Forum on Age, said the new rules were confusing employers and were a contradiction in terms. "If you outlaw age discrimination it is counter-intuitive to leave age limits in the national minimum wage - particularly for the 18 to 21 development bracket, which is clearly restrictive on young people."

She said the EFA would continue to campaign on the issue and that although a training wage was fair, it should not be based on age.

Professional support lawyer Anna Henderson at law firm Herbert Smith said it was conceivable that someone could bring a claim, but added that an exemption within the age regulations meant that the government intended to keep the banding in place.

James Harborne, employment policy executive at the BRC, said the implications of changes to the age discrimination laws on minimum wage had not been discussed enough. Huge confusion existed, he said, about whether under-22s could be paid the adult minimum wage, which rises to £5.35 also on 1 October, without compromising employers' legal status.

Henderson added that the issues surrounding pensions and redundancies could be more complicated still. "There are likely to be a few high-profile claims early on as a result. But at least this would bring some case law and clarity."

The BRC has predicted that the minimum wage increase next week will add another £1.5bn to retailers' costs. It follows the loss of 78,000 jobs from the sector last year after £1.2bn was added to wage bills.