In a dramatic move that some critics are suggesting is like holding a gun to their own heads, Ireland's Catholic bishops have warned they will no longer perform the civil aspects of weddings if marriage is extended to gay couples.

In a concerted effort to delay or even stop the introduction of same sex marriage in Ireland, the Irish Bishops Conference (IBC) has asked the government if it can make oral submissions in opposition to any same-sex marriage provisions at the forthcoming Constitutional Convention.

According to the Irish Independent, the Constitutional Convention has already received more than 1,000 submissions on the issue of marriage equality and it will announce next week which interest groups and individuals will be invited to make oral submissions.

It's understood the bishops want to make their opposition clear in advance of the possibility of a referendum on same sex marriage.

To underline the severity of their objections, the 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 that would include gay marriage.

In Rome in recent weeks the newly elected Pope Francis has been eager to demonstrate he represents a new beginning for the Catholic Church, but the hardline stance of the Irish bishops has reminded Irish massgoers it will be business as usual regarding the church's ministry to gays, critics say.

Currently, for a wedding to be legally recognized in Ireland, it must be solemnized by one of the 5,600 people who are on the Register of Solemnizers. At least 4,300 of these are Catholic priests.

But in a reaction the bishops might not have anticipated, many observers say that bishops unprecedented threat has the potential to backfire spectacularly, however. After decades of sexual abuse claims being ignored, or hidden, or denied and then reluctantly acknowledged, the bishops' threat may not have the moral authority they imagine, critics contend.

In fact, some observers see it as an opportunity to price the church's hands from what is otherwise a civil arrangements. 

'With the removal of one of the main reasons that non-church goers still attend church at all, the bishops could be assembling a circular firing squad,' one observer told the press. 'This threat could actually do what many actually want it to - make marriage a civil contract with no religious associations at all, if the couple so desire. To some this is the equivalent of losing a five pound note and finding fifty.'

In their 10-page submission, the Catholic bishops have reportedly warned that 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 the former Bishop Christopher Jones in the submission.

The conservative Catholic group the Iona Institute, the Council for the Status of the Family and the Evangelical Alliance Ireland are the main religious 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.

Figures from the Catholic organization Accord show that 14,232 Irish people attended marriage preparation courses last year. According to the Central Statistics Office, there were 19,879 marriages in 2011.