Irish politicians are tonight expected to pass divisive laws to legislate abortion in limited circumstances for the first time.
The most controversial aspect of the new laws allows a pregnant woman to seek an abortion on the grounds that she is suicidal.
Several members of the coalition Government are reportedly preparing to rebel over the reforms which will protect a woman's right to a termination if her life is at risk.
Mass protests co-ordinated by pro-life groups, death threats sent to politicians and intimidation of campaigners have exacerbated the already bitter disputes over the reforms. On Tuesday, a group of pro-life activists slept at the front of Leinster House overnight, saying prayers for those supporting the bill and waving placards with graphic images. The vote will take place there by 10pm on Wednesday evening.
A smaller group of pro-choice activists also held a demonstration after camping at the Dail. They carried pictures of Savita Halappanavar, whose death last October reignited the contentious abortion debate.
Up to 10 government members were expected to rebel but the passing of the law looks set to go ahead.
Lucinda Creighton, Minister for European Affairs is the most senior figure expected to vote against the legislation as she opposes the suicide clause. Instead of a termination, she wants alternative therapies offered.
But if she votes against the bill she will lose the Fine Gael party whip and her junior ministerial position.
Ms Creighton has pushed for the legislation to be amended to include adding a rule that would allow the unborn to have legal representation whilst a speedy and intense assessment of women who state they are suicidal is conducted.
Four of her colleagues have already lost the whip and face the threat of being barred from running for the party at the next election as Taoiseach Enda Kenny sticks to his hard line demanding all Government members vote in favour or abandon their posts.
Mr Kenny has insisted the reform is about "all the women of Ireland".
The Protection of Life During Pregnancy Bill 2013 was drawn up following the death of Mrs Halappanavar, an Indian dentist who died in an Irish hospital in October last year after being denied an abortion as she miscarried.
An inquiry uncovered that medics missed an early opportunity to terminate on health grounds and unacceptable clinical practice.
Previously doctors acted under guidance from the Irish Medical Council and law based on a Supreme Court ruling from 1992, known as the X case, that allowed abortion if there was a threat to the mother's life, including suicide.
The case was taken by a 14-year-old rape victim who became pregnant and was refused permission to travel for an abortion. This injunction was eventually overturned by the Supreme Court because the girl had shared suicidal thoughts with her mother.
Ireland was also under pressure after a European Court of Human Rights ruling that a woman in remission with cancer was discriminated against because she was forced to travel overseas for a termination.
Pro- choice campaigners have demanded action and claim Ireland only exports its problem with about 4,000 women registering with an Irish address for an abortion in the UK every year.
Campaigners for abortion to be allowed in other circumstances, such as fatal foetal abnormalities, have been told that it will not be included in any loosening of Ireland's strict regime.
The inclusion of the suicide clause has been the biggest bone of contention, with some opponents arguing it should not serve as legal grounds for abortion, and others claiming abortion in those circumstances could do more damage to a woman's mental health.
Decisions will be finalised today on whether amendments can be made to the legislation but major changes are unlikely.
Following Wednesday's ballot, the bill will be considered by the Seanad - the upper house of parliament.
After that, the legislation will be brought to President Michael D Higgins who will sign off on it and enshrine it into Irish law - provided there are no demands for further amendments, The Government expects the law to be enacted before the Dail breaks for summer on 18 July.
Archbishop Eamon Martin warned TDs who support the bill would be guilty of co-operating with evil.
In a last-ditch appeal by the Catholic Church to urge the Government against enacting the law, the coadjutor archbishop of Armagh said excommunication from the church is a rare phenomenon.
But he warned Catholic politicians might be forced into serious conversations with their priests about their own personal journeys if they vote for the bill.
"The direct and intentional killing of any persons is always gravely immoral," Mr Martin told RTE Radio.
"I can say that knowingly and willingly and intentionally voting to promote abortion, which is the killing of an innocent child, is co-operation in evil and can't be reconciled with your faith."