Workers at 19 Tesco stores are threatening to go on strike in two weeks time.
The Mandate trade union served strike notice on the company this afternoon following a long dispute over working hours.
Over 95% of employees at the stores voted in favour of industrial action.
The strike will take place on July 2nd and it will be followed by two more days of action the following week.
Mandate spokesperson Linda Tanham has accused the company of rolling back on a negotiation it made with workers in 2006.