Writing in the Irish Independent on Tuesday, Hugh O'Flaherty said that the aims of the proposed referendum could be addressed by legislation.
Mr O'Flaherty is the latest prominent legal figure to cast doubt on plans to hold a children's rights referendum.
The Minister for Children, Frances Fitzgerald (pictured), has repeatedly insisted that the Government's promise to hold such a vote this year remain on course.
Speaking on the final day of the special Fine Gael meeting in Co Mayo, Ms Fitzgerald rejected Mr O'Flaherty's views. She said another judge, Catherine McGuinness, had called for such a referendum 20 years ago and it remained the only way children could be fully protected.
In his column, Mr O'Flaherty said that the wording of the referendum is likely to implement the recommendations of an Oireachtas Committee chaired by Mary O'Rourke.
These recommendations were: to treat and protect all children fairly and equally; make the welfare of children a paramount consideration; extend the right to adoption where child's welfare requires; provide education, including free education at primary level; and make sure the State's laws and services match the United Nations Convention on the Rights of the Child.
He said, "These are very laudable precepts but … they are all, or nearly all, to be found in the existing articles of the constitution, in our ordinary legislation or in court judgments."
A constitution, he added, “should contain the basic requirements for the exercise and protection of any right. It is for the Dáil and Seanad to spell out the dimensions of the provision in question and, on occasion, the courts.”
Last month, former District Court judge Michael Patwell also said that he felt that a referendum is unnecessary.
Speaking to Charlie Bird on RTÉ Radio's Marian Finucane show, he said that he believed that the current Constitution applies to adults and children alike. Amending the Constitution to create rights for children could work against parents.
Asked by Bird whether the amendment could work against the parents of a child, Mr Patwell said, “It could do so.” He said, “If you start giving extra rights to any section of society … it could very well work against the other citizenry.”
Mr Patwell said that the Child Care Act already enables social services to put children at risk in care.
A number of other legal and social commentators have already warned that the wording proposed by the Oireachtas committee last year has a number of possible pitfalls.
Constitutional expert and recently appointed High Court judge Gerard Hogan said that the phrase, “best interests of the child,” could be ambiguous.
Everyone, he said, is in favour of the best interests of the child, but, he asked, "Who is going to decide what is in the best of the child, and how is this going to be done?"
He told RTÉ in 2010, “We’re all in favour of the best interests of the child, and there is something of a mother and apple pie dimension to this. But in practical terms you have to ask yourself, when you’re talking about the best interests of the child, who is going to decide what is in the best of the child, and how is this going to be done? And if you’re talking about the State vindicating the rights of the child, you have to remember that this is likely to be officialdom, or some judge making this decision.”
Another Trinity lecturer, Dr Oran Doyle, expressed misgivings about the wording.
In a talk in Bratislava, Dr Doyle said that the proposed referendum poses the question as to who would decide what the best interests of the child were and suggested that Article 42.2.3 of the wording gives a de facto answer to this question, an answer that he said might entail, "greatly expanded state power and greatly reduced parental autonomy.”