IRELAND's Catholic prelates are leading the charge against gay marriage, warning that they will not perform the civil aspects of weddings if marriage is extended to gay couples.
The Irish Bishops Conference (IBC) has asked to make oral submissions to oppose any provisions for same-sex marriage to the Constitutional Convention.
The Constitutional Convention received more than 1,000 submissions on the deeply controversial issue and will finalise, next week, what interest groups and individuals will be invited to make oral submissions.
The stage has been set for an intense debate ahead of the possibility of a referendum on same-sex marriage.
In a detailed submission, Ireland's Catholic bishops have warned that the church "could no longer carry out the civil element" of marriage if there was any change to the legal definition of marriage.
The bishops' stance would affect the thousands of weddings that take place in the church every year if a referendum to extend marriage was passed.
For a wedding to be legally recognised in Ireland, it must be solemnised by one of the 5,600 people who are on the Register of Solemnisers.
Around 4,300 of these are Catholic priests.
The Constitutional Convention, chaired by Concern's Tom Arnold, said the massive response to its calls for submissions is a hugely positive step.
"It means that the convention is seen as relevant to people and the submissions reflect the fact that Irish society is engaged with the issue," said Mr Arnold.
In their 10-page submission, the Catholic bishops say any change to the definition of marriage would mean the church could no longer co-operate with the civil aspect of marriage.
"Any change to the definition of marriage would create great difficulties and in the light of this if there were two totally different definitions of marriage the church could no longer carry out the civil element," said former Bishop Christopher Jones in the submission.
The Iona Institute, Council for the Status of the Family and the Evangelical Alliance Ireland are among the main bodies opposing same-sex marriage.
Amnesty International, the Irish Council for Civil Liberties, the Equality Authority and Irish Congress of Trade Unions are among nine key groups who will press for full marital rights to be extended to same-sex couples.