Taxi drivers have claimed that their livelihoods may be put at risk due to a lack of available taxi rank spaces in Dublin city and surrounding suburbs.
Union representatives say the large number of taxi licences being issued recently has put severe pressure on the number of places available at taxi ranks.
As a result, they say their members are being forced to break the law by joining queues at the end of taxi ranks, despite the risk of receiving a ticket from gardaí and/or penalty points on their licence.
According to Tommy Gorman of the National Taxi Drivers Union, the issue could lead to angry scenes and calls for strike action early in the new year, when many drivers find that they have little option other than to queue at ranks due to the post-Christmas fall-off in business.
However, at least some of the problems are thought to be due to taxi drivers opting to queue illegally at more popular taxi ranks in Dublin's city centre, rather than at less lucrative ranks elsewhere.
Others point out that some ranks are also underused and that other considerations, which must be taken into account when allocating rank space, include the needs of pedestrians and other road users.
Mr Gorman said that about 20 or 30 more rank spaces had been provided by the council and added that Operation Freeflow had operated quite well.
This was largely helped, he said, by a twice-weekly conference call between taxi drivers and others involved in road-related issues and gardaí.
He claimed there were fewer taxi rank spaces for the 9,500 taxi drivers operating in the Dublin area than when deregulation of the industry occurred seven years ago.
He estimated that there were currently spaces for just 500 to 600 taxis in the Dublin area, a figure which he said needed to be doubled in the short term.
While Mr Gorman acknowledged that there was a limit on the amount of space which could be provided for taxis, he said placing a six-month cap on the number of licences issued would help to address the problem of too many taxis competing for rank space.
Typical penalties for parking in a non-designated taxi space included a fine for each offence, plus the addition of a penalty point, he said.
"If a taxi driver accumulates 12 penalty points, they will lose their licence and their livelihood.
"Over the Christmas period, drivers are probably cruising around a bit more because the business is there. But come the 5th of January, where every taxi is going to be looking for space, its going to be like a massive car park."
A spokeswoman for Dublin City Council said it was limited in the amount of space it could provide at ranks and said the problem was a reflection of the increased numbers of taxis in the city.
A recent review of the situation had included a public consultation process to which the taxi driver unions were invited to contribute.
This had led to the size of some ranks being increased and others decreased, as well as the introduction of night-time ranks.
"Street space is at a premium," the spokeswoman said. "We are happy to meet with drivers on this issue."