The committee only learned of the scandals when they were made public
Nearly 14,000 drivers could have their convictions quashed because they were wrongly served with a court summons when they had already paid a fixed charge notice.
Internal auditors in the Gardaí say the issue could affect thousands of drivers.
The Garda Audit Committee has said that it is “very concerned" that senior management kept it in the dark over the breath test and fixed penalty notice scandals.
The committee said it only became aware of the existence of thousands of fake breath tests or unreliable fixed notice convictions when they were made public in March.
It said senior garda management had been aware of both issues over a year previously.
It also claimed that the two high profile announcements from garda management meant the committee was unable to publish its 2016 report by the March 2017 deadline.
The committee was not notified of the announcements in advance.
The Public Accounts Committee is calling for answers from the Garda Commissioner Nóirín O’Sullivan as to why the auditors were not informed.
The Minister for Justice Charlie Flanagan has said he is aware of the issues that have been raised and expects to receive two reports on the issues in the coming weeks.
He said it would not be appropriate to comment until ongoing investigations into the scandals are completed.