Foreign Affairs Minister Micheál Martin said genuine Irish passport numbers were used.
“These numbers correspond to actual numbers on three legitimate Irish passports. However, the identities of the persons recorded on the forged passports do not correspond to those recorded on the valid passports carrying the same numbers,” said Mr Martin.
The department will contact the three Irish citizens who hold or have held passports containing the numbers. Mr Martin requested that the privacy of the three individuals concerned be respected.
Passports in the names of three Irish holders were among 11 European identity papers revealed by Dubai police hunting the hit squad that allegedly killed Mahmoud al-Mabhouh last month.
Some of the individuals concerned reacted with horror to the use of their identities and denied any involvement in the operation.
Israel’s foreign minister said there was no evidence to link Mossad but refused to issue any formal denial in line with a “policy of ambiguity” on security matters.
Avigdor Lieberman said he was sure Israel was recognised as a “responsible” country that held to “clear, cautious and responsible rules of the game”.
Al-Mabhouh died in his hotel room in Dubai on January 20. It is claimed he was suffocated.
Mr Martin said: “Our passport is widely regarded and respected throughout the world as being of the highest quality. We have invested very heavily in extra security features so that our citizens can travel in safety. Actions, which endanger our well earned reputation in this area, have the potential to affect the security of all our citizens travelling overseas. I am determined to maintain the good name of Irish passports. The department is liaising closely with the United Arad Emirates authorities and with the gardaí on the matter,” he said.