SIPTU members employed at the Drogheda plant of medical device maker BD (Becton Dickinson) are to place a picket at the entrance to the facility at lunchtime today.
It is an escalation of industrial action over the planned closure of the plant.
Last week, SIPTU members began a work-to-rule after the union accused management of failing to engage with it concerning the closure.
In July, it was announced that the operation is to be wound down over the next two and a half years with the loss of around 200 jobs.
"Our members have remained patient for months while seeking meaningful engagement with this US-headquartered company but to no avail," said SIPTU Sector Organiser, Andrea Cleere.
"Our members will continue with their industrial action in an attempt to bring about meaningful negotiations with management concerning the future of the plant," she added.
"SIPTU representatives remain committed to resolving this dispute through direct negotiations with management, we are also available and willing to attend mediation," Ms Cleere said.
Yesterday BD said it is to refer the dispute over severance packages to the Workplace Relations Commission (WRC).
"BD has actively engaged and consulted with the trade unions, trade union representatives and BD employees since 3 July when it was announced that a phased closure of our manufacturing facility in Drogheda would take place," a spokesperson said.
"Despite our best efforts to negotiate with all employees and their unions, BD has had to take a decision to refer this matter to the Workplace Relations Commission to move the process forward," the spokesperson said.
"We remain open to re-engaging with all employees and their unions directly and are amenable to mediation to resolve the current impasse," the company said.
