An application to withdraw auctioneer John Finnegan from the Flood Tribunal has been rejected by Justice Flood.
Solicitor Dominic Hussey claimed his client Mr Finnegan was being unfairly investigated as he has never made a payment to former minister Ray Burke.
Mr Hussey said Mr Finnegan is prepared to take the matter to the High Court.
The tribunal was earlier told that Mr Finnegan had acted as a selling agent in 1977 for property at Monkstown in Dublin owned by the Sacred Heart nuns.
It heard that Mr Finnegan was ultimately a beneficial owner of the same property through arrangements he had made with builders Brennan and McGowan.
Mr Justice Flood was told that Brennan and McGowan set up two companies to conceal the purchase.
The companies traded with each other even though they did not have an office and one was subsequently liquidated after the sale was completed.