The Health Minister and HSE are being urged to intervene to avert an ambulance strike scheduled for Tuesday.
500 members of the National Ambulance Service Representative Association are expected to walk off the job.
It is in a row over union recognition.
Fianna Fáil say it comes at a difficult time of year and Minister Simon Harris needs to confirm if contingencies are in place ahead of the strike.
The party's health spokesperson, Stephen Donnelly says a quarter of ambulance personnel will not be available for a 24-hour period.
"This dispute is related to a union recognition issue. NASRA are affiliated to the Psychiatric Nurses Association (PNA) and they have sought to have the dispute referred to the Workplace Relations Commission. However it seems that the HSE is refusing to engage," said Deputy Donnelly.
"It's time the Minister for Health or the HSE intervened to avert 25% of the State's total ambulance personnel going on strike this coming Tuesday," says Health Spokesperson @DonnellyStephen https://t.co/cHnxQIXcml pic.twitter.com/Un3GVi6a30— Fianna Fáil (@fiannafailparty) January 19, 2019
"At such a difficult time of year the HSE should at the very least meet NASRA and the PNA. The HSE is only compounding the pressure on its own services by not discussing the matter.
"All sides – and all unions – need to reach a solution."
Mr Donnelly added: "While it has been common practice not to engage with unions that are not recognised, plans still have to be put in place to protect the public."