Tánaiste Simon Coveney has said he will tell his colleagues at Cabinet that he will support a law to allow terminations up to 12 weeks, if it is coupled with strict medical guidelines.
Mr Coveney said he made the decision after speaking to clinicians and Minister for Health Simon Harris.
This evening he said he believed the changes he was suggesting would mean more people could support the referendum - people who he said came from his "traditionally pro-life" perspective.
He said the informed consent protocol and a 72-hour wait period were very important.
The Tánaiste added that he would be actively campaigning and would not hide behind anything.
Simon Coveney says he will actively campaign in the upcoming referendum on the Eighth Amendment and "won't hide behind anything". pic.twitter.com/PYM1oBeIGt— RTÉ News (@rtenews) March 26, 2018
Last month, Mr Coveney expressed deep concerns about allowing terminations up to 12 weeks, which the Government plans to introduce if the referendum is passed.
The Tánaiste said he believes any safeguards should include a clinical protocol that would be based on the principle of informed consent and would require a doctor to lay out all information and options in an impartial way to a woman who requested a termination.
He also believes there should be a pause period of between 48 and 72 hours between the initial medical assessment and the termination being carried out.
The campaign group, Together for Yes has welcomed Mr Coveney's contribution.
A spokeswoman said "We see it as indicative of a growing concensus of opinions across the country in favour of removing the Eighth Amendment because it harms women."
The Cabinet will consider draft legislation to regulate abortion for the first time tomorrow.
The Government hopes to introduce the legislation if the forthcoming referendum on the Eighth Amendment is passed.
It is expected the bill will explicitly make late-term abortions unlawful on health grounds where the pregnancy is viable.
However, the proposed legislation from Mr Harris will still provide for terminations in emergency cases as is currently the law.
The Cabinet discussions will come nearly four months after publication of the all-party Oireachtas committee's report on the Eighth Amendment.
The draft legislation is expected to be published this week if it is approved by Cabinet. The bill would allow for terminations up to 12 weeks.
In other cases where there is a risk to the life, or of serious harm to the health of a woman, it is understood the bill would explicitly make terminations unlawful where the pregnancy is viable.
Where the viability of the pregnancy is established by two doctors, and the pregnancy is to be ended on health grounds, then it would be done through early delivery.
However, this would not apply in emergency cases.
In circumstances where termination is recommended, the two doctors would be required to certify that there is a risk to the life, or of serious harm to the health of the woman, and that a termination would avert that risk.
They would also certify that the pregnancy has not reached viability. There are separate provisions to deal with medical emergencies.
Govt accused of 'scrambling' to save proposal
A spokesperson for the Save the Eighth Campaign said that the Tánaiste made a "u-turn", saying he has done so because the Government is scrambling to save its proposal.
Speaking on RTÉ's News at One, Niamh Uí Bhriain said the proposal by Government, if passed, would make Ireland one of the most liberal countries on abortion.
She said that Mr Coveney came under pressure to change his mind and she questioned how voters can trust politicians when they are "flip-flopping".
Meanwhile, the Clinical Director with the National Women and Infants programme at the Health Service Executive has said his view of the forthcoming referendum is now "stronger than ever that it’s not our job to get involved in making, or indeed possibly even influencing, making the law, but in implementing it."
Speaking about the current pregnancy screening and scanning that is available in Ireland, Dr Peter McKenna said: "It is very difficult to imagine anything happening that will not increase the demand for early scans."
However he said: "Abortion on demand up to 12 weeks will probably do very little to reduce disability as it’s not easy to find disability before 12 weeks."
Dr McKenna added that the medical profession can adapt to changed circumstances.
"The majority of people would want to put their personal views to one side and help the patient, once it’s within what is considered to be legal within the country."
Dr McKenna was speaking in a pre-recorded interview for RTÉ News at One.
It was his first interview since the Government indicated it would hold a referendum on the Eighth Amendment at the end of May.