Campaigners for marriage equality in Northern Ireland are to attend a briefing in the Oireachtas.
Love Equality, a coalition of six organisations will hold a briefing event for TDs and Senators in Leinster House.
The briefing is co-sponsored by Senators David Norris and Jerry Buttimer.
The group is working to bring marriage equality to Northern Ireland and includes the three regional LGBT organisations: The Rainbow Project, HEReNI and Cara-Friend.
Amnesty International, the Irish Congress of Trade Unions (ICTU) and the National Union of Students-Union of Students in Ireland (NUS-USI) are also involved.
The group have said the campaign enjoys the support of over 50 major employers in Northern Ireland.
John O'Doherty from the Love Equality campaign said: "We wish to thank Senator Fintan Warfield for organising the briefing and to Senator Jerry Buttimer and Senator David Norris for jointly sponsoring the event.
"Almost four years after the successful marriage equality referendum in the Republic of Ireland, and five years after the introduction of equal marriage in England, Wales and Scotland, Northern Ireland is the only part of the UK and Ireland which does not allow or recognise same-sex marriage, despite widespread public and political support.
"In the absence of a functioning Northern Ireland Assembly and executive since January 2017, only the UK parliament can currently remove the ban on same-sex marriage in Northern Ireland.
"However, the UK government remains unwilling to legislate, leaving same-sex couples in Northern Ireland facing continuing discrimination on the basis of their sexual orientation."
"Justice delayed is justice denied. It is unacceptable and unsustainable to have a patchwork of marriage laws across these islands.
"The ongoing denial of marriage equality to people in Northern Ireland is an embarrassing stain on the UK's LGBT rights record and cannot be allowed to continue."
Sinn Féin spokesperson for LGBTQI rights, Senator Fintan Warfield, said: "Civil marriage equality is about protecting our families, neighbours and friends.
"It is about two people making a commitment to share in the ups and downs of life. It is also about ensuring that the state recognises all of our relationships equally.
"These are rights enjoyed by Irish and British citizens in all other jurisdictions. It is an injustice that we continue to see efforts toward equality being blocked in the North."