Exit polls published after Ireland's referendum on abortion suggest a large vote in favour of liberalising the law.
Polls by The Irish Times and RTE suggest about 69 percent voted to repeal a part of the constitution that effectively bans terminations.
The communications director of one of the main anti-abortion campaigns, John McGuirk, has conceded they have lost.
He said: "There are people who are deeply broken-hearted at this outcome."
Mr McGuirk, communications director of the anti-abortion Save The 8th campaign, told Irish broadcaster RTÉ that the people of Ireland "weighed it in the balance and it came down on one side.
"I obviously would have preferred if they had come down on the other," he said.
"There is no prospect of the (abortion rights) legislation not being passed."
The country's prime minister Leo Varadkar, who supported the campaign to change the law, says it looks like Ireland is about to make history.
The counting of votes began on Saturday morning local time (Saturday night NZT), with a result expected early on Saturday evening (Sunday morning NZT).
Thank you to everyone who voted today. Democracy in action. It’s looking like we will make history tomorrow.... #Together4Yes— Leo Varadkar (@campaignforleo) May 25, 2018
Those taking part in the referendum were asked whether they wanted to repeal or retain a part of the constitution known as the Eighth Amendment, which says an unborn child has the same right to life as a pregnant woman.
Broadcaster RTE's exit poll suggested 69.4 percent in favour of the Yes side and 30.6 percent for No. In Dublin, 79 percent of people voted for repeal, according to the RTE poll.
An exit poll released by The Irish Times points to 68 percent Yes to 32 percent for No.
Currently, abortion is only allowed when a woman's life is at risk, but not in cases of rape, incest or fatal foetal abnormality.
The turnout looks to have been higher than that for the country's referendum on same-sex marriage and its most recent general election.
More than 3.2 million people were registered to vote in the referendum, with more than 100,000 new voters registering ahead of the poll.
The referendum was the result of a decades-long debate about abortion in the Republic of Ireland and was the country's sixth vote on the issue.
Where does the law stand?
The now-controversial Eighth Amendment was introduced after a referendum in 1983.
It "acknowledges the right to life of the unborn and, with due regard to the equal right to life of the mother, guarantees in its laws to respect, and, as far as practicable, by its laws to defend and vindicate that right" - meaning the life of the woman and the unborn are seen as equal.
Since 2013, terminations have only been allowed in Ireland when the life of the mother is at risk, including from suicide.
The maximum penalty for accessing an illegal abortion is 14 years in prison.
In 2017, the Citizens' Assembly, a body set up advise the Irish government on constitutional change, voted to replace or amend the part of Ireland's Constitution which strictly limits the availability of abortion.
So the Irish people were asked if they wanted to remove the Eighth Amendment and allow politicians to set the country's abortion laws in the future.
The wording on the ballot paper was: "Provision may be made by law for the regulation of termination of pregnancies."
The ballot paper did not mention the Eighth Amendment or abortion, instead asking: "Do you approve of the proposal to amend the Constitution contained in the undermentioned Bill?"
Those who wanted to retain the Eighth Amendment voted No, while those who wanted to replace it voted Yes.
If a majority has voted yes - as appears to be the case - then the Irish government's recommendation is that women will be able to access a termination within the first 12 weeks of their pregnancy.
However, beyond 12 weeks, abortions would only be permitted where there is a risk to a woman's life or of serious harm to the physical or mental health of a woman, up until the 24th week of pregnancy.
Terminations would also be permitted in cases of fatal foetal abnormality.