Workers at the Lagan Brick plant in Kingscourt in Cavan have voted to take strike action.
The workers voted "almost unanimously" to serve seven day's notice of strike action to the company, according to SIPTU.
The union said that the move comes after the company refused to attend a Labour Court hearing aimed at resolving the long running dispute at the brick manufacturing plant.
Twenty-five employees have been protesting outside the plant since mid-December in a bid to secure better redundancy terms.
Last Monday, the firm issued formal redundancy notices to the employees, which will come into effect in April.