Learner drivers could have to wait over a year to sit their driving test if more testers are not recruited, according to the Fórsa trade union.
Addressing the union's services and enterprises division conference in Galway, official Ashley Connolly said 80,000 learner drivers are currently waiting for driving tests.
But she warned of an anticipated surge in demand for tests because of proposed new sanctions on car owners who allow their vehicles to be used by unaccompanied learner drivers.
Those penalties will include imprisonment of up to six months, or fines of up to €2,000, as well as the confiscation of the vehicle in question.
The current waiting time for a test is 14 weeks, but Ms Connolly told delegates that could rise to 55 weeks - over a year - if more testers are not hired.
She said that the Road Safety Authority is now seeking departmental sanction to establish a panel of up to 100 additional driver testers, who would be available to work in test centres around the country as the need arises.
Fórsa is also calling for a smaller number of extra driver testers to be employed on a permanent basis to address increased ongoing demand for tests triggered by economic recovery.
According to the union, in 2007 there were 126 driver testers and the average waiting time for a test was 19 weeks.
By 2010, the waiting time had fallen to ten weeks, but today, with only 102 drivers, the waiting time has crept up again to 14 weeks, exceeding the RSA target of ten weeks.
Ms Connolly urged the Department of Transport to sanction the panel of additional testers without delay.
The department has said it is working with the RSA to ensure measures are in place to cope with any possible surge in demand for driving tests.
In a statement, it said these initiatives include the recruitment of additional driver testers and the delivery of 120 extra overtime tests per driver tester who participates.
Other measures include initiatives to reduce the number of applicant no-shows at the driving test and to reduce the number of non-conducted driving tests.
The department said the RSA plans to introduce a new test booking system this year that will give applicants more control over their booking and appointment choice.
The RSA is also planning to recruit new driver testers next month.