Retained firefighters have resumed strike action in a dispute over pay and conditions.
Pickets have been placed at retained fire stations across the country, but members will respond to life-threatening emergency calls.
Members of the retained service are part-time firefighters who are paid an annual retainer for being on-call.
The Labour Court had recommended that the retainer be increased by between 24% and 32.7%.
Under the proposals, a firefighter on an annual retainer of €8,870 would see it rise to €11,769.
The main firefighters' union, SIPTU, described the proposals as a major disappointment and members voted by an overwhelming majority to reject the Labour Court recommendation.
The union said that while the percentage increases may appear large, they relate to small retainer amounts and will do nothing to address a recruitment and retention crisis in the retained fire service.
SIPTU has accused local authorities of refusing to agree an emergency cover plan for the strike action.
Division Organiser Karan O Loughlin said: "For nine weeks, the local authorities and the Government have had an opportunity to put contingency measures in place.
"Our members will maintain a high level of cover, even under the current circumstances, but the management will not co-operate."
The Department of Housing, Local Government and Heritage said it is disappointed to see strike action resume and described the retainer increase proposed by the Labour Court as "generous".
"A consistent and acceptable level of service must be maintained," a spokesperson said.
"Refusal to use the Tetra radio system and arbitrary increases to pre-determined attendance of appliances to incidents is counter to risk assessments undertaken and is unacceptable.
"We don't need to be in this position. A resolution is attainable through acceptance of the current Labour Court offer and engagement with the forthcoming national pay talks," the department said.
SIPTU represents around 2,000 retained firefighters across 200 stations around the country.
Members of the retained service engaged in rolling work stoppages last month and had threatened to escalate the action to an all-out strike.
A Labour Court hearing was held on the dispute on 26 June and SIPTU agreed to suspend strike action ahead of the court's recommendation.
The Labour Court also recommended that the size of the retained service be increased by 400 additional firefighters in order to address staff shortages and stated that every urgent effort should be made to fill all current vacancies.
Other recommendations included changes to premium payments, the introduction of community-based fire prevention programmes to allow firefighters earn additional income, and the development of policies on sick leave, maternity leave and parental leave.
