Union officials say the work can be carried out by Emergency Medical Technicians already employed in the service.
SIPTU members in the National Ambulance Service are to ballot for industrial action, up to and including strike action.
The dispute centres on plans to outsource inter-hospital transfers in the Kildare, Dublin, Meath, and Wicklow to the private sector.
Union officials say the work can be carried out by Emergency Medical Technicians already employed in the service.
They claim outsourcing breaches public service agreements and comes after staff rejected WRC proposals on ambulance crewing.
SIPTU, which represents around 2,000 ambulance personnel, is calling on the HSE and Department of Health to halt outsourcing and properly staff the service.

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