The action has been brought by Mark McCrystal, who claims the Government has been using material in its information campaign that is not neutral.
He claims it is designed, intended and likely to promote a particular outcome in the 10 November referendum.
Mr McCrystal claims that the State is in breach of a 1995 judgment by the Supreme Court, known as the McKenna decision.
The McKenna decision held that referenda should be explained to the public in an impartial manner.
He says that he has no objection to the state arguing for a Yes vote, but only by means that do not involve the expenditure of public money.
In his action, Mr McCrystal is seeking a number of injunctions.