Some 93,364 drivers were issued with penalty points in the first 14 months of the system, according to the latest figures.
Dublin drivers accounted for almost 27 per cent of penalised motorists, with drivers holding foreign licences or no licences accounting for 14 per cent.
This "no driver number" category is immune from the points system as the scheme only covers motorists whose details are held on the National Driver Register.
There is no EU-wide penalty points system in place, although the exchange of information between the Irish and British authorities has been raised by the British-Irish Council.
With the "no driver number" category excluded from the statistics, the proportion of drivers who have received penalty points is 4 per cent.
The system, which penalises speeding and seatbelt offences, will soon include careless driving, dangerous overtaking and using a hand-held mobile phone, according to the Minister for Transport, Mr Brennan.
Four drivers have accumulated 10 points each - two points short of automatic disqualification within a three-year period. Two of these drivers are in the Dublin area while the other two are in Donegal and Kerry. Most penalised drivers (88,271) have been issued with two penalty points.
The vast majority of points were issued for speeding offences, while 2,340 drivers incurred points for seatbelt offences. Of these, 177 received points for not having children properly restrained.
Seatbelt offences were introduced in the system last August.
While Dublin drivers accounted for almost 27 per cent of those penalised, they did not have the same high proportion of seatbelt offences. They were less likely to be penalised for not properly seatbelting children.
Welcoming the figures, Mr Brennan said there had been 68 fewer deaths since the penalty points were introduced, compared with the previous 14 months. Some 342 road deaths were recorded last year - the lowest number since 1965.
"With over 400 drivers on six or more penalty points, many of these are now running the serious risk of losing their licences in 2004," he warned.
"Drivers who persist in speeding, ignoring laws on the wearing of seatbelts and driving without insurance will be caught and will get penalty points."
Mr Brennan also outlined a package of road safety measures to be introduced during the year.
The extension of the points system to include the use of hand-held mobile phones while driving will be part of the new Road Traffic Bill, currently being drafted. The Bill, which is expected to take effect in the second half of this year, will also allow the introduction of random breath-testing to detect drink-driving.
New metric speed limits will be introduced in September, while more than 50 new speed cameras will be installed across the State around the same time.
Also later this year, the provisional licence system will be reformed and a new driver testing and standards authority introduced.
Mr Brennan has also promised to introduce measures to address "the unacceptably high level" of motorcycle deaths and injuries.
