Around 65 engineers working for lift company Otis are picketing at Dublin Airport in a dispute over redundancies at the firm.
Pickets are currently in place at the company's offices in Dublin and Cork, and at Terminal Two in Dublin Airport.
The Technical Engineering and Electrical Union claims that tomorrow its striking members from Otis intend to hold rolling pickets, where the picket moves between locations, at shopping centres where Otis is contracted to maintain equipment.
An official from the Union has said the picket at the airport has effectively stopped all work at the new terminal, as around 500 contractors refused to pass the picket.
Between 900 and 1,000 contractors are still working on a daily basis to complete the final phase of the construction of the terminal.
On an average day, between six and nine of those are Otis employees.
It is understood they are carrying out snagging and testing of the equipment their company installed in the building.
The Dublin Airport Authority declined to comment on the effect of the picket, saying the workers did not have a dispute with it.
The action is also being supported by around 15 engineers at Otis' sister company, Irish Lift Services.
The dispute centres on the company's decision to make 17 lift engineers redundant last month.
The workers, and their union, are unhappy that the redundancies were compulsory and not voluntary, because they claim at least 12 staff were willing to leave voluntarily.
The strike was scheduled to begin at the start of July, but the planned action was suspended as the company indicated it wished to reach an amicable settlement.
Both sides met on three occasions last week, but union representatives reported no progress and so the planned strike proceeded.
The workers said they are prepared to provide emergency cover for hospitals and for incidents where people get stuck in lifts, provided the company does not bring in relief engineers from Britain or elsewhere.
