The store is facing legal action from four female shopfloor workers who claim they are paid less than men to do equally valuable jobs at the supermarket chain.
The case, which will be the subject of a preliminary hearing at a Birmingham employment tribunal on Friday, comes as a similar legal action involving 6,000 female Asda employees remains to be settled.
The women from Sainsbury's, three working in the Shrewsbury area and one in Fareham, Hampshire, were among nearly 20,000 people who contacted legal firm Leigh Day after reading about the case involving Asda.
The law firm says it believes the Sainsbury's action could be joined by thousands more female shopfloor staff.
Both cases hinge on determining whether supermarket shopfloor jobs, which are mainly held by female workers, are of equal value to higher-paid jobs in male-dominated distribution centres.
If the Sainsbury's workers win, they could be entitled to six years' back pay for the difference in earnings. New rules which came in late last year also give tribunals the power to require employers that lose an equal pay claim to complete an equal pay audit of their workforce.