The former Fianna Fáil TD, Liam Lawlor, has been questioned about his co-operation with the Planning Tribunal.
The inquiry has heard that he gave a totally false impression of his connection with a Czech company in sworn statements.
A decision is due soon on whether or not Mr Lawlor should be sent to the High Court where he faces a possible jail sentence for non-compliance.
Earlier Mr Lawlor denied that a false invoice he used was a crude forgery.
There were heated exchanges at the hearing when the tribunal chairman, Judge Alan Mahon, said either Mr Lawlor or his London solicitor, Tony Seddon, was lying.
Yesterday, Mr Seddon said an invoice which purported to come from his firm was a crude forgery and not a genuine invoice.
Mr Lawlor admited the unauthorised use of the stationery but denied that he manufactured the invoice himself, by photocopying the company's letterhead.
Des O'Neill SC for the tribunal said Mr Lawlor knew it was a forgery and was refusing to acknowledge this under oath. He said he was continuing to perpetrate an untruth.
This morning he said he could not remember exactly where or how the invoice was written. It was used to cover up and under the counter payment from the sale of his land in Lucan.