Mary Lou McDonald has said the British Government should intervene to introduce same-sex marriage in Northern Ireland if the Stormont deadlock cannot be broken.
Northern Ireland is the only part of the UK or Ireland which has not legalised what supporters term marriage equality.
Polls suggest a public majority back the measure, but the Democratic Unionists espouse the argument that marriage can only be between a man and a woman and have used a petition of concern to veto proposed change at the Assembly.
The Sinn Fein leader attended her first Pride Talkback event in Belfast and said: “If it is the case that Westminster has to intervene then so be it.”
In a reference to the powersharing impasse she added: “That won’t be a badge of success - that will be a mark of failure.”
She said the best solution would be legislation brought through the Stormont Assembly, rather than Westminster where the DUP’s 10 Brexit-supporting MPs are
propping up Theresa May’s minority Government.
Ms McDonald added: “In the absence of the political institutions, it is a matter for both British and Irish governments to ensure that the rights of the LGBT-plus community in the North are fully vindicated.
“The British Irish Intergovernmental conference met last week, it will meet again in the autumn and it must resolve the outstanding rights issues including the right to marriage equality.”
The Sinn Fein president said any change to the petition of concern as part of powersharing reforms needed to be handled carefully.
“The real perversion here is that a mechanism intended to protect minorities and basic rights gets turned on its head and abused and misused.”
The Ulster Unionists, SDLP, Green Party, Alliance and Progressive Unionists were
represented at Monday night’s Pride debate at the Mac theatre.
The DUP were invited but declined to attend.
DUP MLA Jim Wells was notified but said he would “rather walk up the Falls Road in a Rangers shirt”, the organiser said.
Mrs McDonald said: “Those who wish to push back the tides of change can disrupt and
delay but it will never stop the vindication of those rights.
“This is us. We are proud and we are not going away you know.”
Billy Hutchinson, PUP leader, said Northern Ireland needed the same LGBT rights as the rest of the UK.
His party has supported same-sex marriage since 2013, doubling their vote soon afterwards.
“The politicians are way behind the community. It is two people who love each other. This is not about religious beliefs, this is about people’s equality.
“It is British rights for British citizens.”
UUP Assembly member for Upper Bann Doug Beattie leads a taskforce within his party addressing the issue.
He said he thought none of his colleagues at Stormont would support a petition of concern veto on marriage equality because they were democrats.
“We are moving in the right direction but like that super-tanker in the ocean the turning circle is very large and we are moving very slowly.”