Just over three quarters of votes have been counted in the gay marriage referendum in Ireland.
Campaigners are already claiming victory as its predicted they may have won almost two thirds of the vote.
ITV News Correspondent Duncan Golestani reports:
One of Ireland's most senior Catholic clerics has called for the church to take a "reality check" after the gay marriage vote.
Diarmuid Martin, Archbishop of Dublin, called on church leaders to take a look at itself and how it interacts with young people and their views.
Speaking to RTE, he said: "I think really the Church needs to do a reality check.
"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."
Sinn Fein President Gerry Adams has said he thinks that Ireland's referendum vote on gay marriage marks "a huge day for equality."
Speaking on Sky News he said: "I think this is a huge day for equality.
"I also think that given that the government parties were pressing quite rightly for equality in this issue then we need equality in other issues - we need equality in social issues, economic issues we need everything to be equality. So this is a hugely important day for the LGBT community and everybody else."
Justice and Equality minister Aodhan O'Riordain says he is "proud to be Irish" following early predictions that voters backed same-sex marriage by a landslide.
Supporters have gathered at vote counts across Ireland to await the results of the country's same-sex marriage vote.
Both sides have already said early indications show a Yes result is likely but the official results will not be announced until later today.
ITV Correspondent James Webster reports:
Anti gay marriage campaigners the Iona Institute have conceded defeat in Ireland's same-sex marriage referendum ahead of the results being announced later today.
John Murray, director of the religious think-tank, said: "Everyone is saying it is Yes and I'm not going to argue with that."
Campaigners have hailed Ireland's gay marriage vote as a "unifying day" which "sends a strong message to young people across Ireland that they are valued equally."
Alex White, director of elections in the Yes campaign for the Labour Party said: "This has been a real unifying day for all the country and the result shows that.
"Today does not change Ireland. Today confirms a change that has taken place in Ireland over the last 30-35 years."
Commenting on early speculation that the yes campaign had won the vote Mary Cunningham, director of the National Youth Council of Ireland, said the results "sent a strong message".
She said: "This result sends a strong message to young people across Ireland that they are valued equally; and that we want to promote respect and eliminate homophobia."
Ireland's Equality Minister Aodhan O Riordain claims that the referendum on gay marriage has been won by the yes voters today.
O Riordain told Reuters: "I think it's won.
"The numbers of people who turned out to vote is unprecedented. This has really touched a nerve in Ireland today."
Official results are due later today.
Results from the Republic's 43 constituencies will be fed back to the count headquarters in Dublin Castle, where a pattern is expected to emerge from the smaller regions and faster counts around lunchtime.
It is only 22 years since Ireland decriminalised homosexuality. Voters were asked one simple, specific question on whether to amend Article 41 of the 1937 Constitution by adding a new clause to a section titled The Family.
It asked them to support or reject a change to the 78-year-old document which reads: "Marriage may be contracted in accordance with law by two persons without distinction as to their sex." It does not suggest any change to the definition of the family or remove any outdated references in the section, including those that state a woman's place is at home.
Counting is under way in a landmark ballot in Ireland which could see it become the first country in the world to bring in gay marriage by popular vote.
A high turnout is expected, which supporters of the reform believe is a boost for them, with estimates and reports from individual constituencies putting the poll percentage somewhere in the 60s. A result is expected sometime in the afternoon but returning officers have warned it is dependent on how close the ballot is.