Over 25,000 people attended a rally organised by Pro-Life campaigners in central Dublin today, according to official Garda estimates.
The 'Unite for Life' vigil took place on Merrion square with speakers including Tyrone football manager Mickey Harte.
The rally was organised to express opposition to the Government's commitment to legislate and introduce regulations to allow abortion if there is a real and substantial risk to a woman’s life, including the threat of suicide.
Mr Harte told the crowd he was "concerned" at the proposed legislation.
"Ireland is almost unique in the Western world in looking out for, and fully protecting, two patients during a pregnancy – a mother and her unborn child," Mr Harte said.
"We are here to oppose the unjust targeting of even one unborn child's life in circumstances that have nothing to do with genuine life-saving medical interventions".
He continued: "No individual or nation is perfect - we all have our faults and failings but when it comes to life before birth, we have a value system, an ethos which we should proudly share with the rest of the world."
Pro-life spokeswoman Caroline Simons said organisers were 'thrilled' with today's turnout.
"On a bitterly cold January afternoon when it was predicted that the weather would keep people away, Irish people turned out in many thousands to register their opposition to abortion legislation," Ms Simons said.
Ms Simons told the crowd that claims by the Government that abortion was needed to treat threatened suicide in pregnancy had been "completely demolished at last week’s Oireachtas hearings on abortion".
She said: "The psychiatrists who addressed the hearings were unanimous that abortion is not a treatment for suicidal ideation.
"There is no evidence whatever that suggests that abortion reduces the mental health risks of unwanted or mistimed pregnancy. But there is evidence that abortion increases the risk of future mental health problems for a significant number of women.
"If the Government legislates for abortion on the basis of the X case, this legislation would cure no woman of suicidal ideation, but it would put some women's lives at risk."
Prior to the rally the Archbishop of Dublin, Diarmuid Martin, held prayers for “the child in the womb” at St Andrew’s Church in Westland Row.
Separately, a new pro-choice group, Abortion Rights Campaign, was also established and held its first meeting in Dublin this morning.
Pro-choice campaigners also held a counter-demonstration in the capital today, with initial Garda estimates putting the attendance at around 200.
Protesters gather in Dublin for separate abortion rallies