The National Ambulance Service is facing the prospect of disruption next month after SIPTU members served notice of an all-out strike from Wednesday 10 August.
The dispute centres on their terms and conditions of employment.
Earlier this month, SIPTU members voted by 92% to 8% to back strike action.
The union claims that management at the NAS has failed to engage adequately with staff on issues including compensation due under the Lansdowne Road Agreement, an annualised hours system, and development of an intermediate care service as recommended by the Labour Court.
SIPTU Health Division Organiser Paul Bell stressed that staff will provide an emergency service during the strike period.
The union remains available for meaningful discussions, he added.
Irish Ambulance Representative Council chairman Peter Ray said members were frustrated.
They had changed work practices and achieved significant cost savings so the NAS could develop within the financial constraints of the recession, but had received no recognition of their sacrifice, he said.