Nurses and midwives could strike if their pay demands are not met with salary increases in 2019, according to the Irish Nurses and Midwives Organisation.
Speaking at its annual conference in Cork, General Secretary Phil Ní Sheaghdha said that the union is awaiting publication of a Public Service Pay Commission review of staff shortages among nurses and midwives, which is due next month.
Within the following month, the INMO is due to meet the Government to discuss implementation of the PSPC recommendations to address the difficulties with recruitment and retention.
However, Ms Ní Sheaghdha warned that, if members rejected proposals emanating from those negotiations, the INMO will ballot them for industrial action - "up to and including the withdrawal of their labour".
An emergency motion to that effect will be debated at the conference tomorrow.
Ms Ní Sheaghdha noted that the Health Service Executive now has 2,000 fewer nurses compared to 2007, while more people are relying on the public health service.
She warned that, if pay rises did not start to flow in 2019, the staffing crisis would get progressively worse.
She described nurses and midwives as very low-paid front line workers, starting on €28,700, which was between €7,000 and €8,000 behind other entry grade public servants.
Ms Ní Sheaghdha said that was not sustainable considering they are now operating in a global market, where the HSE is competing on a stage where pay levels are "two-fold or three-fold" higher than that.
She said it would be "incredible" if the Public Service Pay Commission failed to recommend pay rises for nurses and midwives, considering the evidence presented to them of the cause and effect link bewteen low pay and retention.
She also rejected suggestions that addressing the nurses' pay demands would trigger knock-on claims elsewhere in the public service.
Almost three quarters of this year's nursing and midwifery interns are considering leaving Ireland when they graduate, according to a survey published by the INMO.
In a bid to address staff shortages in nursing and midwifery, the Health Service Executive has pledged to offer permanent jobs to all eligible graduates.
However, the INMO survey suggests that the incentive is not working.
It found 71% are considering leaving Ireland, while 57% have already been approached by overseas recruitment companies.
79% - almost four in five - say pay rises, as well as improvements in staffing and working conditions, are required to retain nurses and midwifes in the public service.
INMO student and new graduate officer Neal Donohue said the offer of a permanent job for an extremely low paid job with poor working conditions was simply not attractive for nursing and midwifery interns.
INMO passes motion on abortion
Meanwhile, the INMO has passed a motion calling for the right to conscientious objection if abortion is introduced in Ireland.
The motion calls on the union to "safeguard the individual nurses and midwives who hold differing, often strongly held views on abortions, where issues of personal morality and professional ethics co-exist".
It notes that the 2013 Protection of Life During Pregnancy Act makes provision for the statutory right of all healthcare staff to conscientious objection to participation in abortion.
It states that, if the Eighth Amendment is repealed, this right should be upheld and "no nurse or midwife should be vilified or coerced into compromise, because freedom of conscience is not respected, or because staffing levels are at crisis point".