The National Taxi Drivers' Union has claimed that over 1,000 taxis are operating illegally on forged licences or without licences at all, having rented cars from leasing companies.

The commissioner for taxi regulation, Kathleen Doyle, said leasing companies are responsible for ensuring drivers have the appropriate licence. She said she had not come across forgery.

"There are about a dozen taxi leasing companies renting cars and plates to drivers," said union president Tommy Gorman. "We know that they accept either forged small public service vehicle (SPSV) taxi licences or none at all. Many non-nationals rent taxis from these companies and they have not been vetted by gardaí.

"Some Irish drivers do too. Some of these drivers then share the cars with friends or family members. We don't know anything about these people's criminal background. This leaves the general public very vulnerable and it is unfair to legitimate taxi drivers. People deserve a sense of security when they get into a taxi."

Doyle said there was regular enforcement to ensure that all drivers are licensed. Details of the SPSV licence and insurance certificate must be available to the vehicle licence holder and a record held for inspection by the commission on request, she added.

"Anything can be forged. But we have not come across forged licences. Our main checks are carried out on the roads and we'd spot them very quickly. We are working with the gardaí and they are stopping people night and day. We are finding unlicensed drivers. We have about 100 prosecutions pending," she said.