Gardai have admitted that figures posted on their official website about the number of breath tests carried out on drivers over three years were hugely exaggerated.
he wrong figures have been attributed to human error and flaws in the system of compiling and logging the numbers.
According to garda officers, the increase on the real figures ran into "thousands".
And in relation to one period, it was discovered that the figures for roadside breath tests alleged to have been carried out was bigger than the total number of mouthpieces available to the force at that time.
A fresh mouthpiece must be used for each individual test, an officer pointed out.
An investigation was carried out after the errors were spotted in 2015.
As a result, breath tests figures for last year are accurate.
But the numbers published on the website for 2013, 2014 and 2015 all represented a significant increase on the actual figures.
Gardai told Independent.ie that the errors had no impact on the overall number of motorists recorded for failing a breath test as the final analysis depended on the testing that took place in the garda station.
But they acknowledged that the extent of the errors was very embarrassing for the force.
As a result of the investigation, gardai said, the system used to record the roadside tests had now been tightened up and personnel had been warned to be more careful in putting the figures together.
But investigators were satisfied that the false numbers were not the result of a deliberate attempt to exaggerate the number of tests but were due to a series of human error and system flaws.
The full extent of the blunders will be revealed tomorrow morning when gardai hold a media briefing on the website blunders.
Among those attending the briefing will be Assistant Commissioner Michael Finn, who was appointed last year to take charge of roads policing and major event/emergency planning.
The briefing will also be used by the gardai to outline how they are coping with previously identified problems with issuing fixed charge notices for penalty point offences through the post.
Many offenders facing penalty points had their offences struck out in district court hearings after telling the judge that they had not received their fixed penalty notices in the post.