The Supreme Court has reserved its decision in 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 in Dublin had claimed the Government was wrongly using €1.1m of public funds to promote a Yes vote.
That is not allowed under the McKenna judgment.
The case was given priority by the Supreme Court as the referendum takes place on Saturday.
After a two-day hearing the decision of the court was reserved.