Workers at CIE are set to down tools for ten minutes at noon on the day of an attack being launched on Iraq.
"We...do not support a war waged on the innocent people of Iraq. These people are not our enemies and a war on them is not a just war," a joint statement signed by trade union officials from SIPTU, ATGWU and ILDA said.
They said their action will be a "humanitarian gesture of reflection for all those who will lose their lives" during the course of the war.
The unions said they also hope that many Irish will do the same, as "a gesture of this nature can send a powerful message to our national leaders that we do not support this impending slaughter".