Around 150 fire fighters in Cork are taking industrial action in protest at staff shortages which, they claim, are endangering both them and the public.
The industrial action by SIPTU members at Cork City Fire Brigade involves a form of work-to-rule and will escalate, the union says.
Cork City Council has insisted that the industrial action will not impact on the delivery of emergency services.
In a statement, SIPTU said the dispute centres on the failure of Cork City Council to reinstate Ballincollig Retained Fire and Rescue Service, or to provide additional resources to Cork City Fire Brigade to cover Ballincollig.
There were up to a dozen retained fire fighters in Ballincollig at peak. They provided a round-the-clock service to the town, which is 10km west of the city.
"The consequence of this has been to expand the area covered by the Cork City Fire Brigade without providing staff to operate the fire appliance in Ballincollig fire station," SIPTU Organiser Con Casey told RTÉ News.
"Vacancies for retained fire and rescue service members in the Ballincollig area have remained unfilled since September 2021, even though the first recruitment campaign commenced in October 2020."
He added: "It is shameful that Cork City Council should force firefighters, who literally put their lives on the line for their communities, into industrial action in this way. If our members must escalate their industrial action to force a resolution to this dispute, they will."
Notice of industrial action, including strike action, was served on Cork City Council earlier this month.
The council said in a statement it is available to meet union representatives and has invited SIPTU to talks. It has also sought the assistance of the Workplace Relations Commission to help find a resolution to the dispute.
However, Mr Casey said that invitation to talks was not accompanied by a proposal from the council about how the dispute might be fixed.