Superquinn has said all its 19 stores were open yesterday except for butchery counters in some outlets, which were closed as a result of an industrial dispute.
Some 103 butchers are involved in the dispute. Pickets were mounted on some stores after talks linking an 8 per cent pay rise to increased work flexibility ended in an impasse.
SIPTU has said it will apply to the Irish Congress of Trade Unions for a strike ballot of all workers.
Superquinn has accused SIPTU of failing to abide by Labour Relations Commission and Labour Court recommendations.
A company spokeswoman said more than 90 per cent of staff turned up for work yesterday and it expected its stores would continue to operate normally. The dispute relates to stores in Dublin, Naas and Bray.