Some 38,000 people have applied to do their driving test since Minister for Transport Noel Dempsey launched his abortive bid to impose early curbs on provisional licence holders.
Some 10,000 people applied yesterday to the Road Safety Authority (RSA) to undertake a test, although the authority has said that the application flow is "expected and manageable".
Fianna Fáil TDs privately voiced their fury towards Mr Noel Dempsey for his handling of the affair.
"My phone started ringing at five past seven in the morning," one TD explained.
Defending Mr Dempsey yesterday, Taoiseach Bertie Ahern said that extra money from the Department of Finance will be necessary to hire more private-contract driver testers from Swiss firm SGS.
"The backlog of approximately 130,000 should be dealt with by March and the remainder must be dealt with by the summer.
"If we can achieve that, the figures should be brought into line by summer. It will be demanding but I believe there will be a huge amount of compliance in the next number of months," said Mr Ahern.
"Some people have driven with provisional licences for up to 20 years or so, although proportionally, their number is not too high at between 20,000 and 30,000. Many others have not been taking the law seriously. Holders of first provisional licences are supposed to be accompanied by a licence holder, but that rule has not been enforced. By next July, however, everybody must be on the right side of the law when the gardaí start to enforce this measure," he added.
Rejecting Opposition calls to sack Mr Dempsey, Mr Ahern said: "No. I am going to let him get on with the job. That is the important thing. He will not do what he likes. He will try to do his job to the best of his ability and he is doing that."
However, Fine Gael leader Enda Kenny said last night that Mr Ahern's defence meant that Mr Dempsey is "immune from sacking" even if he fails to clear the backlog and offers second provisional licence holders a test by next June.
"The Taoiseach has underscored his own weakness when it comes to holding office holders to higher standards. How can the man who failed to see the problem with accepting large amounts of foreign cash for personal use enforce discipline in his Cabinet?"