The Road Safety Authority has been accused of being "disingenuous" and misleading an Oireachtas committee on waiting times for a NCT.
The RSA said the average lead time for an appointment is currently 18.6 days against a target of 12 days nationally.
Fianna Fáil TD James O'Connor said the earliest available test in Youghal in east Cork when booking online today is 16 January 2024.
"When you go online today, the closest available time in all south Munster facilities is January so I don't know where you are pulling those figures from, they are certainly not being pulled from your website."
He said the RSA figures were not accurate and it was "utterly disingenuous" to claim that the average test lead in time is 18.6 days.
RSA Chief Operations Officer Brendan Walsh said it was not fair to refer to them as disingenuous and he said its data is independently validated by Deloitte.
Mr Walsh also said the RSA figures reflect an average wait time across a week of bookings rather than a moment of time.
Sinn Féin TD Martin Kenny also said some people are waiting four to five months for a test.
Applus Managing Director Mark Synnott said he did not share the narrative of a four to five-month wait.
He said that if a customer wants an earlier appointment, they can put themselves on the priority list and if they do not get a test within 28 days, they are entitled to a free test.
The RSA was also pressed on the 30-week delay for driving tests.
Fine Gael TD Alan Dillon said he did not feel an urgency from the authority to reduce the waiting time.
"Thirty weeks' wait time is absolutely ridiculous especially for young people starting a new job who want to go to college ... I don't feel the urgency there from yourselves to implement emergency measures to get us to 2024."
He said it was an awfully long time for a young person not to have access to a car on their own, especially in rural Ireland.
Mr Walsh said more permanent staff have been added and more temporary testers are currently being recruited.
He said the wait time was not satisfactory but he said it would be fixed by the middle of next year.
Earlier, the RSA said that the backlog was due to an "unprecedented" level of applications combined with staffing issues.
Eligible drivers are supposed to receive a test within ten weeks of applying.
Mr Walsh was due to say that the ten-week average waiting time will not be met until mid-2024.
In his opening statement to the Oireachtas Committee on Transport, seen by RTÉ News, Mr Walsh was due to say that driving test applications this year until the end of August were 170,826 versus 169,237 for the full year in 2018.
He said this was due to population growth, inward migration and an increase in drivers under instruction by Approved Driving Instructors.
The number of applications for learner permits has also increased to record levels and is up 35% compared with the same period in 2019.
Mr Walsh said a previous backlog accumulated during the Covid-19 pandemic was cleared by early 2022 when waiting times fell to six weeks.
The Department of Transport approved an increase in the number of permanent driver testers from 100 to 130 in early 2022 and all these posts have been filled.
An additional 75 driving testers have been sanctioned for a period of two years and recruitment is ongoing.
The RSA is currently providing an average of 4,000 tests per week, up from 3,186 in October 2022.
Deaths on the roads have risen by nearly a quarter this year, according to the RSA.
A total of 130 people have died due in fatal collisions up to 10 September compared with 105 in the same period last year, a rise of 24%.
In addition, almost 850 people have been seriously injured in road traffic collisions so far this year.
The RSA will return to the Oireachtas Committee on Transport next week for a detailed discussion on road safety.
