A bishop warned Mass-goers that abortion was a "criminal practice" and "gravely contrary to the moral law", as the Catholic Church raised the pressure for a No vote in the coming referendum.
A series of pastoral letters starkly warning of the consequences of repealing the Eighth Amendment were issued over the course of the weekend.
Bishop Phonsie Cullinan told the faithful of the diocese of Waterford and Lismore that their vote on May 25 "will determine whether many Irish babies live or die" and the matter was "about life and death".
He described the amendment as the only defence against the "ruthless introduction of the deliberate and awful taking of innocent human life as happens in Britain and elsewhere".
In the diocese of Clonfert, Bishop John Kirby cited the 'Catechism of the Catholic Church' to warn his flock that "direct abortion...is a 'criminal' practice gravely contrary to the moral law".
Stressing that the intentional killing of the baby in the womb was "fatally wrong", he said if there was a Yes vote, the mother would have a choice, but the baby would have none.
"The consequences of what is being proposed are far-reaching. It will not just be about the pregnant woman. Healthcare facilities and workers here may well be obliged to participate in abortions or give referrals to abortion providers, even if they do not believe in abortion," he warned.
Meanwhile, in Kerry, Bishop Ray Browne hit out at politicians, claiming the majority would "support a system of abortion similar to Britain".
He added: "The unborn child does not just become human at birth. The right to life of the unborn child is a fundamental right."
Referring to a recent poll in which 70pc of GPs said they were opposed to being involved in carrying out abortions, Dr Cullinan said: "It is a fact that maternity care in Ireland is one of the best in the world, better than in countries like the US and UK, where abortion is available on demand."
Separately, the Association of Catholic Priests, which represents over 1,000 clerics, said it was concerned that parishes were "allowing their pulpits to be used by campaigners during Mass". It said the practice should be stopped.
Meanwhile, Fianna Fáil Senator Ned O'Sullivan last night said a member of the public had called his presence outside a church "an insult" because of his support for a Yes vote. He was outside his local church in Listowel, Co Kerry, collecting for the Fianna Fáil national collection. He said he was "berated" for standing outside the gates of the church on the basis he was voting Yes.