SIPTU members at the National Ambulance Service (NAS) will take strike action next month in a dispute over updated salary scales.
There will be a 24-hour work stoppage on 12 May, followed by a 48-hour stoppage beginning on 19 May, and a 72-hour stoppage beginning on 26 May.
SIPTU has warned of further strike action in June.
A work-to-rule will also be put in place from 11 May, involving non-cooperation with new procedures or changes.
Last week, around 2,000 SIPTU members in the National Ambulance Service voted overwhelmingly for strike action.
The union has accused the Health Service Executive (HSE) of failing to implement the recommendations of an independent report on updating staff salary scales to reflect changes in their responsibilities and workload.
The dispute involves members working as emergency medical technicians (EMTs), paramedics, advanced paramedics, specialist paramedics and paramedic supervisors.
Members of the Unite trade union in the National Ambulance Service also voted overwhelmingly for strike action last week as part of the same dispute.
"The dispute arises from the NAS's failure to update staff salary scales to reflect changes in their responsibilities and workload over the last 20 years," said SIPTU Ambulance Sector Organiser, John McCamley.
"SIPTU members have been left with no other option but to issue notice for strike action due to this long-running dispute."
"We are calling on the HSE to implement the recommendations of the independent report without preconditions to introduce enhanced pay scales which properly recognise the training and professional level of our members," Mr McCamley said.
The HSE previously said it met with SIPTU and Unite in February and confirmed it was committed to entering further discussion on the substantive elements of Workplace Relations Commission proposals, which included new pay scales for relevant grades that recognise past, present and future transformative change, subject to the financial envelope approved by the Department of Health and with the consent and sanction of the Department of Public Expenditure and Reform.
"This proposal was rejected by SIPTU and Unite, who immediately advised of their intention to ballot for industrial action," the HSE said.
The HSE added that it remains committed to engagement through the dispute resolution processes set out in the Public Service Agreement and calls upon both SIPTU and Unite to also commit to doing so.
