Former taoiseach Charles Haughey directed that a Lebanese girl be given Irish citizenship despite reservations expressed by civil servants, the tribunal heard yesterday.
It is investigating the granting of citizenship to a number of people on residency grounds.
The people were all related to or connected to Mahmoud Fustok, a wealthy diplomat with connections to the Saudi royal family who made a £50,000 payment to Mr Haughey. Mr Haughey has told the tribunal the payment was for a horse.
Former assistant secretary at the Department of Justice Cathal Crowley told the tribunal he attended a meeting in Mr Haughey's office in the early months of 1989 where the case of the Lebanese girl, Faten Moubarak, was discussed.
He told Jacqueline O'Brien SC, for the tribunal, that he was told to attend the meeting by minister for justice Gerard Collins.
He said that at the time the Aliens section of the department believed Ms Moubarak should not be naturalised. Her father had been naturalised in 1982 on the grounds of residency, but the department now suspected that his application was "fraudulent" and that he had not been resident here.
The department suspected that it was also the case that Faten Moubarak was not resident here.
Mr Crowley said his meeting with Mr Haughey was cordial and lasted about 10 minutes. Mr Haughey seemed to know about the reservations that existed. He said Mr Haughey's final words were: "We've heard your objections. Here's what we'll do. Send the forms down here." Mr Crowley said he took this to be in effect a direction from the taoiseach that the application would be granted.
He had no more dealings with the case, but the files showed an application form was filled in and Ms Moubarak was granted naturalisation in May 1990.
Mr Crowley said he did not revert to Mr Collins about the matter as he "thought the minister did not want to be involved".
Former head of the security division at the Department of Justice Stephen Magnier said Mr Haughey raised the matter with him during a meeting some time in the 1988-1990 period.
He told Jerry Healy SC, for the tribunal, that Mr Haughey had a practice of standing in for the minister for justice when the minister was out of the State.
On one such occasion when meeting to discuss a specific item, Mr Haughey, at the end of the meeting, asked if Mr Magnier believed "anything could be done" about the naturalisation of Ms Moubarak.
Mr Magnier had not heard of the case before. When he returned to the Department of Justice he spoke with Bryan O'Brien of the Aliens division who brought the file to his office. He looked through the file and noted the reservations civil servants had in relation to the possibly fraudulent naturalisation of Ms Moubarak's father.
Asked if he discussed the file with Mr O'Brien, Mr Magnier said: "We were both civil servants of long standing. We exchanged glances. We knew straight away that this didn't look right."