Three people who had dealings with the former Fine Gael minister Mr Michael Lowry have refused to attend to give evidence, the tribunal heard.
Mr Lowry said he and his advisers had done all they could to encourage the people concerned to attend. "It is not of our doing," he said.
Mr Jerry Healy SC, for the tribunal, said the three people were: Mr Kevin Phelan, Mr Christopher Vaughan, and Mr Karl Tully.
Mr Phelan is a businessman based in Northern Ireland who acts for Irish investors buying property in Britain.
Mr Vaughan is a British solicitor who acted for Mr Lowry in two British property transactions.
Mr Tully is an official with Irish Nationwide Bank in the Isle of Man where Mr Lowry had an account which he only recently disclosed to the tribunal.
Mr Lowry told the tribunal he put a £25,000 sterling deposit on a property in Mansfield, England, after he was introduced to the property by Mr Phelan.
He said at the time it was intended that Mr Phelan would find investors to fund the other 90 per cent of the £250,000 sterling deal.
At the time of the purchase other investors had not been identified. The property was bought in Mr Lowry's name, using Mr Vaughan as a solicitor.
Mr Lowry said he was contacted by Mr Phelan in late 1997. "I got the impression he thought I could buy London." Mr Lowry said he had to let Mr Phelan know he was mistaken.
Eight to 10 months later, Mr Phelan got back to Mr Lowry over the Mansfield property. In September 1998, Mr Lowry viewed the property and agreed to put down the deposit. Mr Phelan introduced him to Mr Vaughan.
By March 1999 the balance had not yet been paid. Mr Lowry said Mr Phelan got Mr Aidan Phelan, an accountant who was then acting as a financial adviser to Mr Denis O'Brien, interested in the site.
Mr Aidan Phelan, who is not related to Mr Kevin Phelan, agreed to put up the remaining 90 per cent. He proposed to Mr Lowry that they become partners, their interests reflecting their investments.
Mr Lowry said he did know at the time that Mr Kevin Phelan had done business before with Mr Aidan Phelan.
The tribunal heard Mr Lowry met with Mr Aidan Phelan for the first time in 1997, when the media disclosed that a close associate of Mr O'Brien was linked to the provision of Mr Lowry's mobile phone.
Mr Aidan Phelan, he said, had become involved in sourcing a phone for him by way of Mr Denis O'Connor, Mr Lowry's accountant, who knew Mr Aidan Phelan.
He said Mr O'Connor also introduced him to Mr Aidan Phelan when, during 1997, he was looking for a strategic partner for his company, Streamline Enterprises. Mr Phelan acted for another refrigeration company, Masser Hammond.
He met Mr Aidan Phelan on a number of occasions during that year over the matter.
He told Mr Healy he never mentioned these contacts to the late Mr David Austin, his close friend. He did not know that Mr Austin was also friendly with Mr Aidan Phelan.
He denied Mr Austin acted as an intermediary for a payment from Mr O'Brien in 1996.
"Let me assure this tribunal there is no intermediary required for Michael Lowry or anyone associated with me as a conduit for money from Denis O'Brien, because it never happened."
At the time, in late 1996, when Mr Austin paid money into Mr Lowry's Isle of Man account, Mr O'Brien mentioned to an Esat Digifone colleague, Mr Barry Maloney, that he had made a payment to Mr Lowry. After Mr Lowry had returned the money to Mr Austin, Mr O'Brien told Mr Maloney that the payment he had referred to earlier, had become "stuck with an intermediary".
Mr Lowry returns to the witness box on Tuesday.
