The Daughters of Charity are to close Rickard House in Blackrock in Co. Dublin with the loss of 45 jobs.
The facility provides care to 27 retired members of the Daughters of Charity.
SIPTU and the INMO have condemned the announcement.
They say staff were only told of the closure yesterday.
Rickard House is situated on 15 acres of garden and is a purpose built residential centre.
The 27-bed unit was established to provide long-term care, convalescence and respite care to the Daughters of Charity, the Vincentian priests, the parents of the sisters and other family members approved by the Provincial of the Daughters of Charity.
David Field is an organiser with SIPTU.
"The Order notified union members of the proposed job losses at a general meeting on Monday (19th November). The need for investment to keep Rickard House up to standard and other costs were cited as the reason for the closure" he said.
"Both unions had an initial engagement with the Order, following the announcement, which was aimed at exploring ways to keep the facility open and preserve employment" he added.