Multinational companies including Intel could face pickets from 24 February as electricians ballot for nationwide industrial action over pay, according to the Technical Engineering and Electrical Union.
TEEU General Secretary Eamon Devoy said electricians are seeking a 4.9% pay rise from electrical contractors.
He said the increase is due under a Labour Court recommendation which was never implemented.
The ballot result is due on Friday 7 February, and if no settlement is achieved in the interim, 6,500 electricians and apprentices could commence strike action on 24 February.
Mr Devoy said the dispute would hit a number of areas where electrical contractors operate, including multinationals, electricity supply and construction.
He cited Intel, which currently has 2,000 contractors on site, including 650 electricians.
Mr Devoy was speaking as the Irish Congress of Trade Unions confirmed that it is taking a case to the European Court of Human Rights alleging a failure by the Government to ensure the right to collective bargaining in Ireland.
This follows a Supreme Court ruling last May which declared unconstitutional sectoral wage-setting mechanisms called Registered Employment Agreements.
This in turn meant that legally binding protections for workers' pay and conditions in sectors covered by REAs were diminished.
However, it is understood it could take up to four years for the case to be heard.
