Plumbers, fitter, welders and apprentices are picketing outside the National Children's Hospital today.
It's part of Unite trade unions ongoing strike action against employers who are members of the Mechanical Engineering & Building Services Contractors’ Association.
Meanwhile members who are due to work at Lilly, Pfizer, Therma fisher, and Whitegate Refinery sites in Cork are participating in a labour withdrawal today as part of the strike.
They're calling for the travel time allowance, which was cut after the financial crash, to be reinstated.
A four full-day work stoppage is underway since midnight.