The builder Mr Tom Brennan has been accused of lying to the Flood tribunal over a £50,000 donation to former minister Mr Ray Burke.
Counsel for the tribunal Mr Pat Hanratty SC also said Mr Brennan had perjured himself and deliberately not disclosed information about payments to Mr Burke in earlier evidence.
Mr Brennan denied the claims. He said that he had not informed the tribunal about certain donations to Mr Burke as he had not been asked about them.
In 1982 Mr Burke received £50,000 into an Isle of Man account controlled by him from Mr Brennan's company Kalabraki Ltd. Mr Brennan told the tribunal it was a political donation to Fianna Fáil as it was short of money and "there wasn't even enough to pay for sandwiches or drinks" for election campaigners.
Mr Hanratty said asked him why if the money was for Fianna Fáil why was it paid to an account in the Isle of Man held by a Mr Burke and not directly to Fianna Fáil in Mount Street [party headquarters].
Mr Brennan said it was a political donation to "Ray Burke/Fianna Fáil" and as Mr Burke was a senior party member "he would sort it out".
He was also questioned about why he and Mr Joe McGowan made up a £10,000 shortfall on a £60,000 donation to Mr Burke in 1984.
The donation was made through a company called Canio Ltd in which Mr Brennan, Mr McGowan and auctioneer Mr John Finnegan were shareholders.
Mr Hanratty suggested each were to pay £20,000 but Mr Finnegan refused to do so and instead paid £10,000 leaving Mr Brennan and Mr McGowan paying £25,000 each.
Mr Brennan could provide no explanation as to why they made up the amount or why the political donation had to be £60,000.
He denied they made up the difference because they were indebted to Mr Burke in some way.
Earlier Mr Hanratty SC showed Mr Brennan correspondence from that tribunal to him asking for details of any payments from Mr Brennan or any companies associated with him to Mr Burke.
Mr Hanratty said that Mr Brennan had deliberately withheld information about the Kalabraki payment until the tribunal found out about it. He also put it to Mr Brennan he was lying about the true nature of the payment.
Mr Brennan denied this.
His evidence continues tomorrow.