Some 24 workers at the Bulmers brewery in Clonmel are threatening strike action in a row over redundancy terms.
Unite members have voted in favour of industrial action after the company allegedly breached a 2009 collective agreement with the unions when making a worker redundant.
According to the trade union, the company has informed the 24 Unite workers at the brewery that they are not covered by the deal.
Explaining the background to the dispute, Unite regional officer Tony Kelly said: "Despite an unambiguous agreement concluded in 2009 between Bulmers and the unions, the company has now made one of our members redundant on terms which will amount to around half of what was agreed.
"Inexplicably, the company has informed the workers represented by Unite that they are not covered by the 2009 agreement.
"While this dispute only affects the managerial grades represented by Unite, I would like to thank the other unions representing workers in Bulmers for their support.
"Following a unanimous vote by Unite members for industrial action, it is in the company’s interests to continue honouring the 2009 agreement which was negotiated under the auspices of the LRC, pending engagement under the same auspices."