The company is proposing changes to the working conditions of staff who began working with the company before 1996, which will see a reduction in their pay.
Tesco has said it is extremely disappointed with the decision as it has yet to implement planned changes to the contracts of 300 staff.
The outlets in Clonmel and Thurles are among those targeted by the strike action which will impact on 70 store nationwide.
Bill Kelly is Divisional Organiser with the Mandate trade union which represents the workers.
Speaking on Tipp Today he said there are many other staff on effectively the same contracts who have not been targeted.
