Siptu members in Cork County Council have served notice of industrial action tomorrow morning, in a row over staffing levels in road maintenance crews, and other services.
The staff will down tools for four hours from 8.30am tomorrow.
In a statement, Siptu said the row concerns a management refusal to recruit more staff.
Siptu organiser Con Casey, said: "This action results from a management refusal to engage with the workforce planning process and recruit more staff to adequately delivery statutory services."
He said a Co Council proposal issued last Friday was "insufficient to address the issues involved".