Workers at 'Section 39' organisations are to hold indefinite strike action.
The move has been backed by the executive of the Fórsa trade union.
The community and voluntary organisations involved are funded by the HSE to provide day and residential services for people with mental health difficulties and disabilities among others.
Staff have been involved in a long running dispute over pay, saying that staff doing similar roles within the HSE are paid significantly more.
The union has also pledged to fund the wages of striking staff.