Members of the Connect trade union are taking strike action at street lighting company Enerveo, which provides services to several local authorities.
The action is part of a dispute over redundancy payments.
"Enerveo recently announced that it was bringing to a conclusion its operations in Ireland and will not be seeking to retender for any of its current contracts," according to Connect General Secretary Paddy Kavanagh.
"The company is refusing to provide its workforce with redundancy payments in line with those previously provided in the sector," he said.
Connect members voted in favour of strike action in a ballot conducted last month and notice of industrial action was served on the company for Monday 8 July.
It was initially deferred pending talks aimed at reaching a solution to the dispute but the negotiations broke down yesterday.
The indefinite strike action involves pickets being placed at locations where the company carries out its work - including Enerveo depots, local authorities and some construction projects.
In a statement, Enerveo said that following a comprehensive review of its business, it made the decision to withdraw from the Irish market earlier this year.
"As a result, we are undertaking a redundancy programme and are working with affected colleagues and their representatives," a spokesperson said.
"We are also mindful of the impact of industrial action on our customers and are working with them to ensure continuity of critical services.," the company added.
