This investigation was launched initially by the Department of Foreign Affairs last May when internal checks at the Passport office detected irregularities in two passports.

Its alleged that the passports were real but they contained false information.

Further checks last autumn highlighted discrepancies in another 3 documents.

The garda inquiry has been ongoing since last year and as part of the investigation a man and a woman both in their 30s who work at the Molesworth street office in the city centre were arrested yesterday and taken to Pearse garda station for questioning.

The man remains in custody where he can be held for up to 24 hours and the woman was released without charge last night, with a a file being prepared for the DPP.