The leader of the Catholic Church in Ireland sparked a backlash when he again suggested priests could refuse to conduct the civil part of a wedding ceremony if the same-sex marriage referendum is passed.
Archbishop Eamon Martin said the church had not yet decided on its position if the Yes campaign won the day.
"We would have to look at legislation to see is it possible for us to continue to stand over our ministers being involved in civil ceremonies," he said.
Couples who marry in a church effectively enjoy a combined civil and religious ceremony during the one service.
A church boycott would effectively mean that couples would not be officially married by the priest and would have to go elsewhere for the civil portion.
Dr Martin said the issue would have to be fully discussed by the Conference of Bishops and may not arise at all if the referendum is rejected.
He also raised other issues which need discussion, including the teaching on marriage and sex education in schools if the 'Yes' side wins.
Yes Equality spokesperson Grainne Healy accused the Archbishop of confusing the issue.
She said: "We believe that he has merely served to confuse issues, in particular the distinction between church or religious marriage and civil marriage. This referendum is solely concerned with civil marriage and its constitutional status.
"And in England, Wales and Scotland, the Catholic Church have continued to perform civil marriage as part of the religious service following the introduction of civil marriage equality there."
Tánaiste Joan Burton later weighed in on the row, arguing that the Catholic Church had changed its views on marriage over the years - and may do so again in the future.
Ms Burton cited the example of "mixed marriages" between Catholics and Protestants, that were carried out in the early morning at side altars. She said that was common up to 50 years ago but then the church changed its view.
But Ms Burton said the forthcoming referendum was about changing civil marriage - and had no impact on religious marriage.
"We have had these debates over a long period of time," she said.
"The church, like every organisation, reflects the changes in society. But what the church decides is entirely a matter for the church," Ms Burton said.
Labour's referendum campaign director, Communications Minister Alex White, said these matters could be dealt with. He said that church schools deal already with divorce being legal in State law, and prohibited by the church.
Launching his party's campaign for a 'Yes' vote on May 22, Green Party leader Eamon Ryan said that "as a proud Catholic" he was voting 'Yes' to gay marriage.
"I, as a Catholic, will vote 'Yes' on the basis of my informed conscience," Mr Ryan said.
Asked about the comments by Dr Martin on ending civil marriage in church, Mr Ryan cited Pope Francis's statements that the church was essentially made up of the people. Mr Ryan said that over time the Church could change its stance.