The Supreme Court has begun hearing an appeal against the High Court's rejection of a claim the Government's Children's Referendum information campaign was biased towards a Yes vote.
Mark McCrystal of Kilbarrack Road, Dublin 5, had claimed the Government was wrongly using €1.1m of public funds to promote a Yes vote, something which was not allowed under a landmark judgment of the Supreme Court - the McKenna judgment.
The case was given priority by the Supreme Court as the referendum takes place on Saturday.
Senior Counsel Richard Humphries told the court today if the decision of the High Court last week was allowed to stand, then the McKenna judgment would be "hollowed out" and become little more than a decorative item, drained of life, force and substance.
The Government was entitled to be partial, but not use public funds, he added.
The campaign was not fair, equal and impartial and did not meet the McKenna threshold, he said.
Since the McKenna judgment, things had moved on and the Referendum Commission was established to inform the public on referenda.
There was no room for a parallel Government campaign, Mr Humphries said.
Last week, the High Court ruled that there was no bias in the Government's information campaign.
High Court President Mr Justice Nicholas Kearns rejected Mr McCrystal's claim the Government's information campaign was designed, intended and likely to promote a particular outcome in the referendum.
The judge said he was satisfied that the campaign was neutral and balanced, and that its primary aim was to inform the public about the referendum.
He said the Government's campaign could not be said to plainly favour a particular outcome, and so it could not be said to be unconstitutional or wrongful.
Mr Justice Kearns rejected Mr McCrystal's claim that the Government's television, radio and print media advertisements encouraged a Yes vote and described them as "particularly inoffensive".
He said they could not be interpreted to sway voters in any way other than in encouraging them to vote.