Learner drivers applying to sit their driving test may have to wait until the end of next April.
The Road Safety Authority (RSA) has estimated that a person applying for a driving test will face a 30-week wait as a result of the backlog caused by Covid-19.
Figures show 15,111 people have been scheduled to take a test over the next five weeks.
However, 43,192 are waiting for a test appointment.
With around 10pc of all test candidates failing to show up on the day, the RSA is appealing to people to let them know if they cannot attend, as appointments can then be reallocated.
It said the numbers waiting for a test have increased due to two factors.
One is that the test service was shut down for months, during which time only emergency tests were conducted.
The second is that they only began testing on July 29, and are operating at around 75pc capacity per examiner because of pandemic restrictions.
The RSA said the reduction in capacity is a direct result of the measures it had to introduce in order to comply with Covid-19 health and safety measures.
"When the service was suspended in March, the average waiting time for a driving test was less than six weeks," a spokesperson said.
"We estimate that a person applying now could face a 30-week wait.
"Those whose test appointments were cancelled when the service was suspended due to Covid-19 have all been offered a test date.
"In the interests of fairness, test appointments are being offered to people in the order of application date and for cases of essential workers.
"We are also operating a cancellation list and will place candidates who need an urgent test on that list.
"However, the cancellation list will also become quite lengthy as customers are cancelling less frequently."
The RSA said a number of measures are being undertaken to increase capacity levels in the service.
These include increasing the number of tests an examiner can perform each day.
When the service resumed, examiners were restricted to carrying out five tests per day.
However, this has increased to six since September 14.
Additional overtime tests are also being scheduled, including on Saturdays.
The service is also in the process of re-hiring up to 19 examiners who were previously employed on temporary contracts.
This could bring the number up from 118 to more than 130.
It is also examining the recruitment and training of new examiners.
However, it will be the second quarter of next year before these new recruits begin to make an impact on waiting times.
Ten per cent of all test candidates do not show up, and 6pc of tests are not conducted because customers have incorrect documentation.
The RSA said it would appeal to any candidate who cannot attend their test appointment to let them know by completing the webform on rsa.ie.
"In this way, the test can be reallocated to another candidate on the cancellation list," it said.