Services at State training agency Fás will be disrupted by pickets today over the continuing row over the Government's decentralisation plans.
Only a handful of the 400 staff have so far signed up for the plan to move Fás to Birr, Co Offaly.
Siptu, which represents 280 workers, claims staff will not be promoted unless they leave their jobs in Dublin.
Union members are to picket offices today in Baggot Street, Clyde Road and South Circular Road, Adelaide Chambers and the Ecollege in Tallaght.
A protest is also being planned for next week outside the offices of Tom Parlon, the Minister of State in charge of the decentralisation plan.
Contacts are continuing between Siptu, Fás management and the Department of Finance in an attempt to resolve the row.