Northern Ireland is a discriminatory backwater for gay and lesbian people, a human rights organisation has claimed.
Amnesty International also warned that a legal challenge was likely if a proposal legalising same-sex marriage was rejected by the region's devolved Assembly tomorrow.
Patrick Corrigan, Amnesty's programme director, said: "Marriage should be available to same-sex couples in Northern Ireland, just as it is in Scotland, England and Wales and may soon be in the Republic of Ireland.
"Northern Ireland is being left behind as a discriminatory backwater for gay and lesbian people.
"If politicians again abdicate their responsibilities, once more it will be left to the courts to uphold the right of all citizens not to face discrimination."
Gay marriage is a divisive issue in Northern Ireland.
The proposal to have it legalised has already been rejected by the Assembly three times and is again set to go to the floor of Parliament Buildings tomorrow.
DUP members have consistently voted against the motion and have used a contentious Stormont voting mechanism to essentially block it.
Mr Corrigan added: "Those opposing equality for gay and lesbian couples are on the wrong side of history."
Last week DUP health minister Jim Wells sparked a wave of controversy after he claimed children were more likely to be abused or neglected in "non-stable" marriages.
Video footage showing Mr Wells saying that "facts show you certainly don't bring a child up in a homosexual relationship" was released following the election hustings event in South Down.
Mr Wells apologised for his remarks but is still facing calls for his resignation from political opponents.