Retained firefighters have begun a campaign of industrial action.
Their union SIPTU has accused the Government of failing to address a worsening recruitment and retention crisis in the service.
Members of the retained service are part-time firefighters who are paid an annual retainer to be available for call-outs.
The industrial action, which begins today, will see members engaging in a campaign of non-cooperation with work outside of responding to emergency calls.
This will involve refusing to engage in training exercises and drills.
It will also see radio calls through the emergency centres being replaced by the use of mobile calls to fire service management.
If there is no resolution to the dispute, rolling strikes will begin from 13 June which will see a series of one-day work stoppages at 50% of fire stations at any given time.
If there is still no resolution, an all-out strike will begin on 20 June.
SIPTU represents around 2,000 retained firefighters across 200 stations around the country.
While larger urban areas have full-time fire brigades, many parts of the country rely on retained firefighters.
Call for action to attract more retained firefighters
In January, SIPTU members in the retained fire service voted overwhelmingly in favour of industrial action.
The union said that many firefighters are unable to take their leave entitlements due to staff shortages and have seen their incomes drastically reduced due to reductions in call outs over the last number of years.
They are required to provide 24/7 emergency response and restrict their movement, at all times while on call, to within typically five minutes travel time of their fire station.
"Our members are responsible and will do what is required to ensure public safety isn't compromised, but equally the Government must recognise that they have let down firefighters by not tabling serious proposals which they acknowledge exist to address the crisis in the service," said SIPTU Sector Organiser Brendan O'Brien.
Talks aimed at resolving the dispute broke down last month.
Minister for Housing, Local Government and Heritage Darragh O'Brien has published a report on the future of the retained fire service which contains a number of measures aimed at addressing problems in the service and his department said that work is under way to begin implementing the recommendations.
Last week, Mr O'Brien told the Dáil that he is confident the industrial dispute can be resolved.
In a statement, the department said that SIPTU has confirmed that throughout the strike action it will comply with the provisions of the Code of Practice on emergency disputes.
"This reflects the professionalism and dedication of its retained fire service personnel to ensure that fire services are provided even in a strike situation and have confirmed that it will respond to all emergency calls involving life-threatening situations," the department said.
