SIPTU has warned the Government that the wording of the gender equality referendum must include "care" in all its forms and anything less would be unacceptable.
The referendum is due to take place at the end of November and a wording was due to be agreed by mid-May.
However this week the Minister for Finance Michael McGrath signalled that the referendum planned for November could be delayed.
He said it would not proceed until there was agreement on a "settled wording."
The Government is expected to get an update on the issue later in the month.
SIPTU's Deputy General Secretary, Ethel Buckley, descried the forthcoming referendum as a critical moment for Irish society.
She said it was important that all those who provide care, including people in the home and in the wider community, are recognised.
Speaking at the Countess Markievicz summer school in Sligo, Ms Buckley pledged that SIPTU would work with civil society organisations to build a national consensus on the importance of care.
The Citizens' Assembly on Gender Equality and a subsequent Oireachtas committee recommended a three-pronged referendum.
Remove gendered language referring to women in the home; ensure the role of care is supported; and create a more inclusive definition of family - moving away from the constitutional definition of the family based on marriage.
The Electoral Commission, which will run the information campaign on any referendum, has said it will need 14 to 16 weeks to prepare a proper campaign.
If the referendum does not go ahead in November, the next most suitable date would be early spring 2024.
In an open letter to Taoiseach Leo Varadkar last month, the National Women's Council, One Family, SIPTU, Family Carers Ireland and Treoir said time is needed for a national conversation on the Family, Care, and Gender Equality referendum.
Almost four months after the wording was due to be finalised the five groups said they are worried the delay could signal a Government "backtrack" and are calling for "urgent clarification".
