The businessman Ben Dunne is to give evidence to the Mahon tribunal as part of its new investigation into lands near Dublin airport.
Mr Dunne has given extensive evidence to the Moriarty tribunal over payments made to the late Charles Haughey.
Details of his appearance next month were listed on the tribunal website yesterday. It is not known whether his appearance is linked to inquiries into the ownership of lands known as Cargobridge.
The tribunal revealed yesterday that Ciarán Haughey, son of the former Taoiseach, may have been one of the beneficial owners of a company called Abervanta Ltd, part of the consortium which owned the Cargobridge lands.
Lobbyist Frank Dunlop, who was retained by the Cargobridge consortium, said yesterday he had only heard about Mr Haughey's involvement the day before at the 14th hole at the K Club.