Thousands of health and community workers will go on strike from October 17th.
The Irish Congress of Trade Unions (ICTU) said the action is over Government "failure" to address funding and recruitment issues.
A ballot for industrial action at the ICTU health group of unions took place after Workplace Relations Commission talks collapsed in July.
Subsequently, Fórsa, the Irish Nurses and Midwives Organisation (INMO) and Siptu carried out ballots, and all three unions reported high levels of participation and "overwhelming" support for strike action.
In total, 18 services will be brought to a halt on an indefinite basis. The list includes employers like the Irish Wheelchair Association and Enable Ireland.
ICTU said that although these services are largely State-funded, in some cases staff have significantly worse terms than HSE counterparts at similar grades.
ICTU general secretary Owen Reidy called for a cast-iron commitment that pay parity will be restored, a “very defined” road map about how that will happen and a mechanism to be put in place to ensure future pay increases will be paid for workers in the community sector.
Service users and their families are “foursquare” behind the workers, he told RTÉ radio's News at One.
"Before the economic crash in 2008, virtually all of these workers had a link with the public service because they essentially carry out a public service or their organisations are publicly funded. When the economic crash took place, these workers suffered the big cuts like everybody else.
"But when it came to restoring that and when it came to catching up, we are way, way behind. These workers are on average about in excess of 10 per cent behind their peers in the public sector."
Mr Reidy said the way to address the disparity was to restore pay and ensure the people who were doing the same work, sometimes in the same location, were being treated equally.
Workers had been lobbying and unions had been negotiating to seek a resolution, he said.
"They have been on the streets on and off for the last 10 years. We've had one-day strikes over the last few years and the Government have not listened.
"We have the funding to address this issue, but there doesn't seem to be a political will and it's a really serious step to take industrial action, particularly in the sector. And these workers don't take it lightly. They know that it will cause implications.
"We've come to the conclusion that only an indefinite strike from the 17th of October has the potential to bring this to a conclusion that we would hope for in the next three weeks. There's a window and we would hope the funders take that opportunity seriously and address the issue."
Mr Reidy said unions would happily return to the Workplace Relations Commission. "At the end of the day, if these services fall apart, they will because people are leaving them, there's a recruitment and retention crisis. The State is legally obliged to fill the gap. We're saying be proactive, you have the money, sit down with the unions and negotiate.
"Essentially these organisations exist because the State has failed in its responsibility to provide these services, but they are wholly and exclusively funded by the State. These are workers who are the embodiment of what we call essential workers. They are carrying out a public service, but they are being treated less favourably than their peers in the public service.
"There's a way to resolve it. There's a road map there if the employers take the opportunity. But we've three weeks to fix this or else we are going to see serious industrial action already."
Pay parity
Confirming it has been served notice of the industrial action, Enable Ireland said it supports its workers regarding pay parity and called on the Government to implement pay alignment.
"For many years, Enable Ireland has advocated for pay parity for our staff and we fully support staff demands to permanently align pay scales on an equitable basis with their peers in the HSE and Section 38 voluntary organisations," the group said.
"Our valued employees are essential to deliver the critical services to children and adults and their families for which we are contracted by HSE to provide each year.
"This pay inequity has created a recruitment and retention crisis for Enable Ireland’s services resulting in significant vacancies in teams across children’s and adult services.
"High vacancy and staff turnover rates negatively impact the quality and quantity of services we can offer to children, adults and their families. This issue will continue to impact the long-term sustainability of Enable Ireland," the statement added.
The group said it will engage with Fórsa, Siptu and the INMO over the coming weeks in an attempt to minimise disruptions to services, however, they admitted they do not yet know how they will be impacted.
"We will keep staff, parents and service owners informed of the planned strike action and its impact on individual services over the coming weeks once we have more information," Enable Ireland added.
