Passports issued in 1990 to Sheikh Khalid bin Mahfouz and his family expired in December 2000, the House was told. The Minister for Foreign Affairs, Mr Cowen, said the question of revoking them did not arise.

However, Fine Gael's Foreign Affairs spokesman, Mr Jim O'Keeffe, sought the revocation of Irish citizenship of Mr Mahfouz and his family because he was a brother-in-law of Osama bin Laden and "evidence has been produced that Sheikh Mahfouz has been a major financial backer of the international terrorist network headed by his brother-in-law".

Later, the Minister of State for Justice, Ms Mary Wallace, said that while Mr O'Keeffe's concern was understandable the basis of it "would appear to be entirely based on speculative reports in the media which are based simply on a family connection".

Revocation of a certificate of naturalisation was a serious matter where the Minister had to show the legal requirements had been fulfilled. However, "if the circumstances of any particular case warrant revocation" the Minister for Justice would have no hesitation in doing so.

Mr Cowen had made a personal statement in the House yesterday to correct information he had given last week to Mr O'Keeffe that there was no record that passports had been issued to a named person and his family.

The error arose because the name supplied to the office was incorrectly spelt and the computer system was "relatively old and has limited search possibilities".