Separate investigations have been launched by Dublin City Council after two employees admitted taking part in a scam whereby Irish driving licences were illegally issued to an international crime syndicate for €1,500 a time.

The Sunday Tribune understands an internal audit at the Dublin city and Ballymun branches of the motor tax office uncovered irregularities in up to 150 Irish licences that had been issued to members of the public.

The two major internal probes are ongoing but it is understood that two female staff members have admitted their part in the scam, which is thought to have netted them up to €225,000.

Dublin City Council has refused to comment on the investigations, but staff members are extremely concerned that, while the irregularities were discovered last July, gardaí have still not been informed about the fraud.

A routine audit of licences found that a fake Romanian driving licence had been exchanged for a legitimate Irish licence and further investigations determined that an unusual amount of international licences – mainly from Romania and Albania – had been exchanged for Irish licences.

It then emerged that extra driving privileges – such as for vans and articulated lorries – had been improperly added to many of the licences without the recipients actually taking the tests to qualify them to drive the vehicles.

An audit of the entire driving licence system was then ordered by city council management and two names repeatedly came up as having been involved in issuing the suspect licences.

Both staff members were interviewed and admitted that they had been paid up to €1,500 per licence. The two women are linked to each other through their respective partners.

It is believed that an Albanian gang is behind the scam and that individuals were being sent in to deal directly with the two staff members, who would make sure that they were given valid licences.

It is understood a female, who works at the Ballymun office, has been suspended on full pay while a worker from the branch on Queen Street has not been suspended.

A spokesman for Dublin City Council replied: "We have no comment to make," when the details of this story was put to him.