The marriage rights which will be enjoyed by gay people in the Republic of Ireland "must be shared by citizens in the north", politicians have said in the wake of the country's historic referendum on the issue.
Northern Ireland is now the only part of the UK which does not allow gay marriage, after England, Wales and Scotland legalised it last year. Politicians in Belfast are under growing pressure to either introduce legislation through the province's Stormont assembly or allow its citizens to decide for themselves in a one-off vote.
A mass rally in support of equal marriage is due to be held in Belfast on 13 June, supported by the Irish Congress of Trade Unions, human rights group Amnesty International and gay rights group the Rainbow Project, which said Northern Ireland was now "the only region in Western Europe where marriage equality is not a reality".
A legal test case has also been lodged in the Belfast courts by an English couple, which is expected to be heard in November.
Belfast's devolved Stormont assembly rejected a motion to legislate for same-sex marriage for the fourth time last month.
The Democratic Unionist party and a majority of Ulster Unionists are against the change, but their representatives are likely come under increasing pressure to address the issue in the coming weeks.
Deputy First Minister Martin McGuinness, whose party Sinn Fein campaigned for a Yes vote in Ireland, said: "Politicians, particularly in the north need to reflect on this progress. The world is moving on and Ireland is taking the lead. Pride in Ireland has taken on a whole new meaning."
Caitríona Ruane, Sinn Féin MLA for South Down, said the resounding Irish referendum result suggested that change was inevitable north of the border. "The marriage equality rights that will be enjoyed by Irish citizens in the south must be shared by citizens in the north," she said.
The Republic is the first country in the world to grant gay and lesbian couples the right to marry by popular vote. Mr McGuinness called for a similar referendum to be held in Northern Ireland during the general election campaign, but the idea was rejected by the unionist parties.
Colum Eastwood, SDLP MLA for Foyle, said Northern Irish politicians of "every hue" should consider the result of the referendum very carefully.
"Soon the North will be the only area in these islands to enforce a ban against same sex couples expressing their love through marriage," he said. "That cannot continue."
In Europe, same-sex marriage is now legal in Belgium, Denmark, Finland, France, Iceland, Ireland, Luxembourg, the Netherlands, Norway, Portugal, Spain and Sweden - leaving Northern Ireland increasingly isolated on the issue.
In the Republic, new laws on gay marriage are expected to be passed by the Dail parliament before the summer recess.
Couples who would like to hold a wedding will then need to give a registrar three months' notice, meaning that Ireland's first gay wedding ceremonies are not expected until the autumn.
The country's tourist body immediately announced plans to capitalise on the publicity surrounding the vote, targeting nine regions in a marketing blitz designed to promote Ireland as an attractive place to hold a wedding or honeymoon. Tourism Ireland has named the campaign "Ireland says I do".
Reacting to the result, which saw 1.2 million Irish citizens vote in favour of equal marriage, one of the country's most senior Catholics said the church needed a "reality check".
Diarmuid Martin, the archbishop of Dublin, said it showed the church needed to reconnect with young people to regain its traditional moral authority in Ireland.
"We [the church] have to stop and have a reality check, not move into denial of the realities.
"We won't begin again with a sense of renewal, with a sense of denial. I appreciate how gay and lesbian men and women feel on this day.
"That they feel this is something that is enriching the way they live. I think it is a social revolution."
WHERE WE STAND IN AUSTRALIA
Despite repeated attempts to make same-sex marriage legal by pro-equality MPs, it is still not recognised in Australia.
in 2013 a Same-Sex Marriage Bill was passed by the state legislature of the Australia Capital Territory in New South Wales, allowing several gay weddings to take place before the country's highest court ruled it unconstitutional.
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