Nurses working in the emergency department at Mayo University Hospital, who are members of the Irish Nurses and Midwives Organisation (INMO), are to begin industrial action on 3 November.
The dispute relates to staffing levels at the hospital.
The action will initially take the form of a work-to-rule which could be escalated to strike action.
According to the INMO, there is currently a deficit of over ten whole time equivalent (WTE) nurses in the emergency department at Mayo University Hospital, with a further 28.5 WTE nurses required to meet the safe staffing levels outlined in the HSE's own Safe Staffing Framework for Emergency Departments.
"Our members are working in a department that is persistently overcrowded and chronically understaffed," said INMO Assistant Director of Industrial Relations for the West Colm Porter.
"Our members are very disappointed that it has come to this, but unfortunately, they feel the risks being posed to patients due to ongoing understaffing problems have become too significant and that their concerns are not being taken seriously," Mr Porter said.
The union said that following a balloting process and proceedings at the Workplace Relations Commission to resolve the issues, members feel that recent actions of management do not demonstrate a genuine attempt to protect their safety.
A spokesperson for the HSE West and North West said it has been working with the INMO under the auspice of the Workplace Relations Commission over a number of weeks.
"We remain open to further engagement with our staff and their representatives and will continue to work within the process to afford all parties the necessary time to work through the matters at hand," the spokesperson said.
The HSE said that Mayo University Hospital is currently progressing a number of vacancies in the ED.
"Once these posts are in place MUH will have completed the recommended baseline staffing standards which will bring then in line with the National Safer Staffing Framework for Emergency Departments," it said.
