More than 1,000 people a month currently do the Small PSV licence examination monitored by the Dublin Carriage Office. Around four-fifths of those have been achieving the 70 per cent score required.
A written test examines their understanding of the rules of the road, as well as their knowledge of the Dublin City and county area covered by the licence.
"It's an awful lot of correcting test papers at the moment, since deregulation," a spokesman at the office said. "We're really snowed under."
The Carriage Office originally had responsibility for exams and vehicle specification for taxis, hackneys and limousines, but all this is now the responsibility of the Department of the Environment.
Annual testing which was also carried out by the two PSV garages attached to the office has been farmed out to the National Car Test operation. Apart from licences, the staff are now using their resources more for accident investigation.
The office still has the responsibility for lost property in taxis. At any time it has up to 1,100 items, mainly wallets, mobile phones, even children's buggies. There's a 65 per cent restoration rate, but calls come from five times as many people as they have property for.
With 1,000 people a month taking out taxi licences - there are around 8,700 taxi plates currently out there - there's potential for that side of the work to increase dramatically.