Retained firefighters are escalating their campaign of industrial action in a row over pay and conditions.
The SIPTU trade union said that fire stations would "go dark" from 8am this morning, with no internal communications other than life-saving information.
For the last nine weeks around 2,000 retained firefighters nationwide, represented by SIPTU, have been engaged in rolling industrial action - seeking better pay and conditions with pickets placed across 200 retained fire stations.
The part-time personnel are paid an annual retainer for being on-call.
The overwhelming majority of the members recently rejected a Labour Court recommendation aimed at resolving the row - a proposal they described as a major disappointment.
SIPTU has accused the Government of failing to respond to legitimate concerns.
SIPTU said if the escalation in industrial action does not encourage management back to the talks table, then from next Saturday, an additional one station will close each week in each county.
