SIPTU members in the Retained Fire Services are to ballot for industrial action over fears reduced crewing levels will pose risks for firefighters.
It follows a directive - issued by the Department of the Environment - which would see attending crews reduced by one member.
Retained firefighters are fully trained, but are not employed on a full time basis and are instead paid on a per callout system.
It is estimated that retained firefighters make up about two thirds of Ireland’s firefighters.
The Department insists changing the crew number would simply keep Ireland in line with international norms.