Fórsa has backed a proposal for indefinite strike action in a number of community and voluntary sector agencies funded by the Health Service Executive.
The union has accused the Government of 'foot-dragging' when it comes to addressing pay and conditions inequality in the sector.
Fórsa says it will cover the wage costs of striking workers, adding that the action is likely to involve hundreds of health and care staff in a number of agencies selected by the union.
Several one-day strikes were held at community, voluntary and healthcare organisations across the country last year as part of a campaign by Fórsa, SIPTU and the INMO demanding better pay and conditions.
Unions say that health and social care professionals employed in agencies funded by the HSE are paid significantly less than equivalent workers employed directly by the HSE and other state bodies.
'Section 39' organisations are contracted to provide services on behalf of the HSE for a funding grant in accordance with Section 39 of the Health Act 2004.
The Department of Health has said that because such organisations are privately owned, setting pay rates for their staff is not a matter for the Government.
A HSE spokesperson said that Section 39 staff are not direct employees of the HSE.
"However, we have indicated our willingness at being party at any 3rd party process, such as Workplace Relations Commission (WRC) conciliation," the spokesperson said.
"The resolution of these matters is not within the remit solely of the HSE," they added.
Fórsa General Secretary and President of the Irish Congress of Trade Unions Kevin Callinan said the union will ballot for indefinite industrial action in a number of organisations.
"As one of the main representative unions involved, Fórsa has decided to call time on the Government's dragging of its own feet on this issue," Mr Callinan said.
"Services will simply be brought to a halt. At this stage, no other course of action will drive the point home.
"Up to a third of experienced professional health and care staff are leaving their jobs in these agencies every year to take up better remunerated employment with the HSE and elsewhere."
Fórsa said that while last year's limited strike action garnered strong support from across the political spectrum, neither the Government, Department of Health or the HSE have since taken any meaningful action to address the issue.