Campaigners for a No vote in the Marriage Equality Referendum say the head of the Referendum Commission has contradicted himself.
Mothers and Fathers Matter claim there is a contradiction between comments Justice Kevin Cross made on radio today, and in a newspaper interview last week.
Today he said surrogacy was not an issue in the referendum, but last week he discussed how it would be "difficult but not impossible" for the Oireachtas to pass laws giving preference to straight couples.
Mothers and Fathers Matter legal advisor Tom Finegan says if surrogacy was not a factor, Justice Cross would not have had to make his comments last week.
Mr Finegan said: "He did appear to contradict himself based on his previous remarks published in the Irish Times, so I think it is important again to distinguish between the statutory effects and constitutional effects.
"No person, other than an Oireachtas member, has any direct say on statute law."
Politicians supporting the Yes vote have again insisted surrogacy has nothing to do with the referendum debate.
Fianna Fáil Justice Spokesperson Niall Collins says concerns about surrogacy in Ireland are a "red herring" which the public should not buy into.
Mr Collins said: "The fact is when it is ultimately regulated by way of legislation in this country, there will be nothing stopping anyone from going to a foreign jursidiction and obtaining a surrogacy service in any event anyway.
"So from that point of view, it doubly reinforces why this (surrogacy) is completely bogus to the question that is being presented."