Irish premier Leo Varadkar has denied assertions that abortion could still be decriminalised in the Republic without the referendum being passed on Friday.
Mr Varadkar said it was not possible to reduce the threat that women face of up to 14 years in jail unless the Republic's people chose to repeal the eighth amendment of the Irish Constitution.
The Taoiseach made the comments after opposition TD Eamon O Cuiv said the laws could be changed to decriminalise women even if citizens voted against changing the constitution.
Voters will head to the polling booths to decide whether they want to remove the eighth amendment, which gives equal right to life to the unborn child and to the woman, and allow parliament to liberalise the laws to permit terminations up to 12 weeks of pregnancy.
Under the current laws women who procure an abortion can face up to 14 years in prison, but can travel abroad for one without sanction.
Mr Varadkar rejected Mr O Cuiv's claims in the Dail yesterday, saying parliament had already tried to decriminalise abortion but it was refused on constitutional grounds.
He said the amendment means the right to life of the unborn, of a foetus of a few days' gestation, is equal to the life of the woman.
The Taoiseach added: "The state must vindicate that right - that is why such harsh and tough penalties are applied."
Mr O Cuiv, who is advocating a 'No' vote on Friday, told RTE that changes could be made to remove the offence. The Fianna Fail TD said he was not in favour of prosecution of women who terminate their pregnancies.
"We can change the statute book in any way," he said, adding that nobody has ever been prosecuted.
The current debate has been bitter, with polls suggesting that young urban voters will largely choose 'Yes' and that older provincial people will opt for the status quo. But the arguments have been followed closely - particularly by the Churches - in Northern Ireland, where abortion is also illegal except in extreme circumstances.
Catholic Primate Archbishop Eamon Martin recently said: "The Supreme Court (in Dublin) has told us that once you remove the eighth amendment, there is no recognition at all for the rights of the unborn.
"Once that is gone I find it difficult to believe that we would not move to probably becoming one of the most liberal regimes in the world."
The Presbyterian Church has also come out clearly against a 'Yes' vote. It described the proposed legislation as "regressive, incompatible with human dignity, and morally unacceptable".
The Church advised members in the Republic to vote against change. However, the uncertainty about the outcome is reflected in the two other main Protestant Churches.
Church of Ireland Archbishop of Armagh Dr Richard Clarke and the Archbishop of Dublin Dr Michael Jackson have come out strongly against a 'Yes' vote.
They said: "Unrestricted access to abortion in the first 12 weeks of pregnancy, or indeed at any stage, is not an ethical position we can accept."
However, individual Anglican leaders have taken a different line. Bishop Michael Burrows of Cashel said: "I will be voting for repeal because I believe, as I did in 1983, that the text of the 'eighth' is incorrigibly flawed. I believe sufficiently in parliamentary democracy to hand the matter to legislators, and indeed to trust them."
The Methodist Church, like the other Protestant denominations, is opposed to "abortion on demand", but also recognises in cases such as rape, incest and fatal foetal abnormalities there may be grounds for termination.
However, Methodist lay leader Dr Fergus O'Ferrall has accused the Churches of "simply virtue signalling to their more traditional constituencies".
He added: "I and other Church leaders and members will be voting 'Yes'. I am focused on how, both as Christians and citizens, we may value and protect... both the sacredness of human life and the health and well-being of women."