The Psychiatric Nurses Association (PNA) has announced an 'escalating campaign' of industrial action including three days of planned strikes.
Members of the PNA last month voted 95% in favour of taking action.
It comes amid a dispute over the recruitment and retention crisis in the health service.
The association's board today met and agreed on their campaign of action.
Members will initially work no additional hours on 31st January and 1st February.
That'll expand the following week with three days of no additional hours on 5th, 6th or 7th February.
If the dispute continues, members will then engage in strike action on 12th, 13th and 14th February.
PNA Office Board met today and agrees escalating campaign of action comprising: 1) members will work no additional hours on 31st Jan and 1st Feb, 2) no additional hours on 5th, 6th or 7th Feb, and 3) strike action on 12th, 13th and 14th Feb.
— PNA (@PNA_IRL) January 10, 2019
The INMO has previously announced that its members will strike on those same February dates if their own dispute with health officials isn't resolved.
The PNA - which has around 6,000 members - has called on both the Department of Health and the HSE to engage with them in a bid to resolve the dispute.
It said: "Recruitment and retention of nurses within the Irish healthcare system needs to be addressed with realistic proposals from Government as a matter of extreme urgency."
General Secretary of the PNA Peter Hughes said his members are over-worked and under-paid.
He explained: "Our members are worn-out doing overtime - you can only do so much overtime.
"It's unsustainable to expect the nurses in the services to maintain the services as they are - and that's no improvement in services. They're very frustrated."
Ireland's nurses and midwives are also planning to go on strike for 24 hours on Wednesday January 30th.
That strike centres on low wages as well as recruitment and retention problems.
The INMO says should the dispute go unresolved, there will be further 24-hour strikes on February 5th, 7th, 12th, 13th and 14th.