The Supreme Court will rule tomorrow on an application by the Pro Life Campaign to allow it to be heard in the forthcoming appeal about the extent of the rights of the unborn.
Lawyers for the group told the court that arising from concerns over recent developments, it wished to be able to make submissions to the court on legal matters.
They said the group could bring 25 years of expertise on the rights of the unborn.
The application was opposed by the State, who said a partisan group in the forthcoming referendum should not be seen as having its views promoted over others.
Senior Counsel Benedict Ó Floinn told the court that the Pro Life Campaign appreciated the appeal was due to get under way on 21 February and if it was joined, it was not seeking to have that date changed.
During the exchanges with lawyers this morning, the Chief Justice, Mr Justice Frank Clarke, noted that "at the end of the day" this was an immigration case.
He said the court would only consider the wider issues to the extent that it needed to, to decide the appeal in the context of the immigration case.
The State has appealed against a finding by the High Court in 2016, that the "unborn" has constitutional rights in addition to the right to life in the Eighth Amendment.
Mr Justice Richard Humphreys ruled in the High Court that the unborn was a child within the meaning of Article 42a of the Constitution and has rights the State is required to protect and vindicate.
The State will argue the High Court got it wrong in deciding the unborn has constitutional rights extending beyond the right to life.
The appeal arises from an immigration case involving a Nigerian man, his Irish partner and their child, who was not yet born when the legal proceedings were initiated.
The court heard there is no dispute between the sides on the facts of the case.
The court's judgment may affect the wording of the forthcoming referendum on the repeal of the Eighth Amendment, which gives the unborn an equal right to life to that of its mother.
The court and the State have previously said they are anxious to have the case heard and decided as quickly as possible in light of the referendum.
Mr Justice Clarke urged both sides to give some consideration to the kind of orders they wanted the court to make in the case.
He said the court was anxious to make sure they did not discover a complication in the middle of the hearing that had not been envisaged.
The appeal is due to take two days before a seven-judge court, beginning on 21 February.
There will be a further case management hearing on Friday.