The ABP food group confirmed this morning that 355 workers have been let go temporarily from its plant at Cahir, Co Tipperary.
The plant is a flagship facility for ABP, one of the largest privately owned food processors in Europe. The Cahir facility employs 650 people and slaughters cattle and produces and packs products for retailers.
In a statement provided to RTÉ, the company said "a further 182 jobs are threatened before the end of the week".
ABP has been blockaded for some weeks. Local negotiations had been taking place with protesters during that period.
The company said production has ceased in Cahir, adding that the job losses are "as a direct result of the ongoing illegal blockade. The protestors have stopped any product going in to or leaving the site".
ABP said it was dismayed that the blockade of its plant was continuing even after agreement was reached with the main farming organisations to resolve the dispute.