Several committee members are calling on her to resign
Cabinet ministers have again stated confidence in the Garda Commissioner Noirin O'Sullivan, despite her being criticised by the Public Accounts Committee (PAC).
It says it was "unacceptable" of her not to inform the Government, or the State auditor, about financial irregularities at the Templemore training college.
The report is the product of two months of public hearings by the PAC.
Its major finding centres around events in July 2015, when Commissioner O'Sullivan was informed about the financial irregularities at Templemore, but told the State auditor she had nothing to report.
The report has also cast doubt about Commissioner O'Sullivan's account of what she did when she found out.
But the findings go beyond her: they also find that several gardaí effectively shut out outside scrutiny, and withheld information - even from their internal auditors.
However Justice Minister Charlie Flanagan says he believes Commissioner O'Sullivan can successfully tackle problems in garda culture.
In response to the report, Mr Flanagan says: "The findings and recommendations of the PAC report will be examined carefully to see what actions are necessary and appropriate on foot of them.
"The garda authorities have stated that they understand the gravity of the issues identified in the Interim Audit Report and are taking comprehensive steps to progress its recommendations as quickly as possible.
"The independent Policing Authority is also overseeing the implementation of the recommendations of the Interim Audit Report and I expect to receive its first report shortly."
He also says further investigations are underway, including an investigation by the Garda Síochána Ombudsman Commission, on foot of a referral from the commissioner of suspected fraudulent activity in relation to certain EU training funds.
And Transport Minister Shane Ross says he also backs Noirin O'Sullivan in her position.
"I haven't seen the PAC report, I haven't read a word of it - so I certainly have confidence in the Garda Commissioner at the moment, yes.
"I haven't seen the report, but I do have confidence in the Garda Commissioner".
The Policing Authority, meanwhile, said it will discuss the findings of the report next week.
In a statement, the authority noted it is undertaking a review of "aspects of the corporate governance in the Garda Síochána".
"The recommendations in the Committee’s report in relation to structures and governance of the Garda Síochána are very timely and will be of relevance to that work," the statement adds.
While Sinn Féin members of the PAC, Mary Lou McDonald and David Cullinane, say the findings are "damning" and that Commissioner O’Sullivan can no longer continue in her role.
Deputy McDonald says: "Commissioner O’Sullivan effectively signed her resignation letter when she wrote to the Comptroller and Auditor General on 31st of July 2015 telling him that there were no irregularities to report in respect of the accounts of An Garda Síochána.
"This was four days after she says she first became aware of the irregularities at Templemore Garda College.
"She took the decision to withhold information regarding those irregularities from the office of the Comptroller and Auditor General, despite them being of such a level as to warrant a full internal investigation.
"This was a contravention of her statutory role as an accounting officer.
“Similarly, she failed to inform the Minister of the issues, despite being advised to do so under Section 41 of the 2005 Garda Act."
Deputy Cullinane adds: "The committee hearings that informed this report, reveal a garda management that is in open conflict with itself, and seems to have coalesced around two broad groups – the civilian element and the garda element."
Labour TD Alan Kelly is the vice-chair of the committee.
He says that the conclusions show the position of the Garda Commissioner is untenable, and she should resign.
"Following extensive hearings on the financial irregularities at the Garda College and the way in which it was handled, I believe the conclusions and recommendations leave the Garda Commissioner in an untenable position.
"As the report concludes, protecting the reputation of the force seems to have come before any other concern with hugely damaging consequences.
"The evidence presented showed that the Commissioner knew of the issues in the College on or before July 2015.
"As the report concludes, it is unacceptable that she failed to act to ensure the Comptroller & Auditor General was informed without delay when the mismanagement first came to light.
"Instead it took 10 months, and was not done by the accounting officer.
"Allied with the failure to promptly inform the department and the lack of action on recommendations made by the internal audit unit, it shows the management weaknesses at the top of our police force.
"Two years on from July 2015 most of the changes required have yet to be completed up to the current day, which is unacceptable", Deputy Kelly adds.
Additional reporting: Gavan Reilly, Jack Quann and Michael Staines