Up to 30 staff members at Kilkenny County Council have started industrial action in a row over pay.
The members of the SIPTU and Connect Unions in water services claim they are not being paid for being on-call out-of-hours like colleagues in other sections.
The action will see them refuse to operate their recording systems and hand-held devices and switch off their phones when their shifts end.
A union representative said the action could escalate if their issues are not dealt with.
A council spokesperson said they are monitoring the situation.
