Fianna Fáil Deputy Leader Éamon Ó Cuív will face a claim for damages and may be cited for contempt of court for leading a protest in the grounds of the Ashford Castle Hotel at the weekend.
Barrister James Dwyer, counsel for the hotel's owners, told Mr Justice John Edwards that Mr Ó Cuív had led the protest against the alleged closure of a public right of way in blatant defiance of a High Court injunction.
"It was an entirely inappropriate course of action for him to take," Mr Dwyer said.
"A significant number of people, including Mr Ó Cuív, blatantly ignored the court order which was read out to them. We intend to have him joined as a defendant to the proceedings."
Mr Dwyer said the hotel owners, Ashford Castle Estate Ltd and Ashford Castle Properties Ltd, would be seeking damages from all defendants and asking the court for a declaration that no public right of way existed through the grounds of the estate.
He said there would probably be a significant delay in the full trial of the proceedings coming before the court and the owners were agreeable to the lifting of an injunction against two existing defendants on their undertaking not to take any further action against the hotel.
They are Hugh Lavelle Cong, Co Mayo, and Sile Gibbons, Quiet Man Café, Main Street, Cong, who, respectively, are chairman and secretary of Cong Community Council.
Mr Dwyer told the court that it had been announced on local radio last week that a protest would be held at a closed-off entrance to Ashford Castle on Friday evening.
On this basis, the owners had obtained an interim injunction on Friday afternoon restraining the two officials of the community council from going ahead with the planned protest.
He said the court order also applied to anyone else "with knowledge of the making of the order" from participating in the protest. The order had been read out to all of them, including Mr Ó Cuív, when they had assembled.
The court injunction prohibited the defendants from obstructing the entrance, roadways and bridges at the Ashford Castle Estate and prevented them from interfering with or obstructing the movement of people entering or leaving the hotel grounds.
Mr Dwyer, who appeared with barrister John Kiely, for Ashford Castle, had told the court the dispute had arisen out of a decision taken by the hotel owners during The Quiet Man Festival in August.
During the event, in order to protect guests and patrons of the hotel, the owners had restricted traffic and closed off and manned a number of gates on the estate. Gates near the estate's helipad had remained closed since 30 August.
A group of people, including members of the community council, had held an hour-long protest against the closure of the gates and, with cars, had blocked a bridge, causing inconvenience to some guests who were trying to make flights at Shannon Airport.
The hotel owners later received a letter stating the community council would take action to maintain the right of way and a major protest had been advertised on local radio for Friday 23 September with an intention to march from the front gates to the hotel.
The hotel, fearing serious disruption, had applied to the court for injunctions.
