Hundreds of Asda workers are holding a rally and march in Leeds over the details of a new contract.
The protest by staff from across the country was organised by the GMB union.
Asda is offering staff a higher wage in exchange for a new contract which will introduce unpaid breaks and a requirement to work over bank holidays.
Asda said it would increase the pay “of more than 100,000” staff. The GMB said the “highly-profitable” firm “could afford to treat staff better”.
The marchers are voicing their opposition to the change called contract 6.
Speakers addressed the crowd in City Square before a march which will pass Asda’s headquarters in the city and finish at the nearby Tetley Brewery site.
GMB national officer Gary Carter said: “Asda is a multibillion-pound, highly-profitable company and it can afford to treat staff better than this.
“We’re calling on Asda to come back to the negotiating table and give this dedicated workforce a fair deal.”
Richard Burgon, Labour MP for Leeds East, who addressed the rally, said: “I think Asda bosses are treating staff not in the right way they deserve.
“It’s a race to the bottom by a very profitable company.”
Mr Burgon added workers had “no other option” than to march after “widely rejecting” the policy.
Asda said the new contract was “an investment of more than £80m, and ensuring that everyone doing the same job is on the same terms and conditions”.
A company statement added: “The retail sector is undergoing significant change and it is important that we are able to keep pace with these changes.
“The overwhelming majority of our colleagues have signed on to the new contracts and while we appreciate that some of our colleagues find the changes more unsettling, we do not want any of them to leave.”