Archbishop Diarmuid Martin of Dublin has lashed out at politicians who respond to the concerns of the 'No' side with "broken gramophone-like quick soundbites".
In an address at All Hallows College, the country's second most senior bishop said the soundbite culture couldn't minimise the significance of what would change if the referendum is passed.
Publicly announcing his intention to vote 'No', he told diocesan communications officers that he does not usually make public his voting intentions.
However, he felt compelled to make his views known due to an article in the 'Irish Catholic' newspaper suggesting he had "confused" the press on his attitude to the referendum in a recent Iona Institute address.
He added: "A pluralist society can be creative in finding ways in which people of same-sex orientation have their rights and their loving and caring relationships recognised and cherished in a culture of difference, while respecting the uniqueness of the male-female relationship.
"I know that the harshness with which the Irish Church treated gay and lesbian people in the past - and in some cases still today - may make it hard for LGBT people to accept that I am sincere in what I am proposing," he acknowledged.
In his All Hallows address, the archbishop suggested that the proposed change to Article 41 is not simply about extending accessibility to marriage, but a real change in the definition of marriage.
"Marriage is not simply about a wedding ceremony or about two people being in love with each other," he stated.
The archbishop said marriage, in the Constitution, is linked with the family and with a concept of family and to the mutuality of man and woman as the foundation for the family.
As no person exists who is not the fruit of a male and a female, genetic parentage is not irrelevant, he said. "We are all children of a male and a female and this must have relevance to our understanding of the way children should be nurtured and educated."
However, Dr Martin underlined that this was not the same as saying that people in differing marital and other relationships cannot be good parents,"much less to deny that they even deserve the title parents".