Over 1,600 cars have been impounded from unaccompanied learner drivers since new legislation was introduced in December.
New garda figures also show that 2,311 people have received penalty points and fines since the start of the year for not displaying 'L' plates.
The data was released as part of a new campaign aimed at encouraging long-term learner permit holders to sit a driving test and to ensure compliance with learner driver regulations.
The Road Safety Authority said there are 41,316 people on their fourth or more learner permit for a car or B category licence.
8,663 of those drivers are on their tenth or successive learner permit.
RSA Chief Executive Moyagh Murdock said: "the practice of people continuing to drive on learner permits without ever taking a test is unacceptable and unnecessary in today’s circumstances.
"While we have seen an 11% decrease in the number of people holding a fourth or more learner permit this year, it’s simply not enough".
Ms Murdock also said "passing your test could mean lower insurance costs in the order of 20-30%, and, more importantly, make you a better, safer driver".
Following the introduction of new legislation in December 2018, unaccompanied learner drivers and the owners of the car they drive, face stiffer penalties.
Chief Superintendent Paul Cleary, from the Garda National Roads Policing Bureau, said the campaign "is about making the roads safer for all road users".
He said: "Learner permit holders need to get the message that the learner permit is not a full licence and that they must be accompanied while driving by a fully qualified driver.
"They also must have 'L' plates on display at all times, otherwise they risk penalty points, a fine and the car being impounded".
Chief Superintendent Cleary said: "If the owner of a vehicle has knowingly allowed a learner permit holder to drive unaccompanied, those owners may also face prosecution".
The RSA said the average waiting time for a driving test nationally is now just over six weeks.
A new website has been established to assist learner permit holders where information can be found on how to access the driving test service and to prepare for the test.