Psychiatric nurses have voted to take industrial action over shortages of staff and resources in mental health services.
The Psychiatric Nurses Association, which represents around 5,000 psychiatric nurses and students, said 87% of those who voted backed industrial action up to, and including, strike action.
The PNA Board will meet on Thursday to decide on the timing and form of industrial action, but it is understood that it is unlikely to start for two weeks.
The industrial action would probably commence with non-cooperation with administrative duties, moving up to protests, and culminating in stoppages if issues were not addressed.
PNA General Secretary Designate Peter Hughes said the vote reflected members' frustration at the worsening problem of understaffing in the mental health services at both acute and community levels.
He estimated that there were already 600 nursing vacancies in the sector, with a further 400 looming due to retirements.
He claimed the Health Service Executive had failed to bring forward a realistic plan to address the crisis in the short and long term.
The PNA met Minister for Health Simon Harris last week and set out proposals to address staff shortages and to plan for the growing demand for newly qualified psychiatric nurses in the coming years.
Mr Hughes called for a comprehensive HSE plan containing measures to retain existing staff and to grow the number of student training places for psychiatric nursing in order to address the current unsustainable situation.
It is understood the PNA proposals would include the possibility of re-hiring retired nurses to plug gaps.
A spokesperson for the HSE said its Director of Human Resources had already held a meeting with the PNA last week.
He added that the HSE was considering the ballot result as well as proposals put forward by the PNA, and is committed to addressing all issues raised by the union.
Speaking on RTÉ's News at One, Mr Hughes said the HSE needs to apply a two-pronged approach to staff shortages in the area of mental health.
There needs to be a focus on retaining nurses currently in the system and also on the recruitment of new nurses, he said.
Mr Hughes said payment for those in training needs to be increased because there is the danger that graduates will move to the UK as the salary there is much more attractive.
He also said the recruitment process needs to be streamlined and the process sped up, as it can take up to six months to recruit a new nurse.
