Tesco workers in Carlow could be about to join the picket lines.
Mandate began balloting members in 23 additional stores last night, after management failed to respond to proposals put forward by the Union on Friday.
Six out of the 10 stores that voted last night opted not to join the picket while the store in Carlow was among those to vote in favour.
Tesco urged Mandate to re-think its strike and to accept an existing Labour Court Recommendation to end the dispute.