The chief executive of the Housing Executive (NIHE) told the Public Accounts Committee he was embarrassed to come before them to answer criticisms made in an Audit Office report, on 12 September 2012.
Dr John McPeake was giving evidence for the committee's inquiry into NIHE management of response maintenance contracts.
He said 29 people had been interviewed by a disciplinary panel in connection with NIHE's discredited maintenance contracts with the Red Sky company.
Five of these people had since retired and eight had received formal written warnings - the most severe form of penalty.
Speaking about the issue of breaches of standing orders and overpayments to contractors, Dr McPeake said: "I don't have the confidence yet to tell you we have this completely solved."
Will Haire, the permanent secretary of the Department for Social Development, explained the "complex structure of reports" into contracts and governance at NIHE.
Dr McPeake told members NIHE accepted the findings of the report on governance and had instigated a review of reporting arrangements within the organisation.
Sinn Fein's Michaela Boyle, who chairs the committee, said it was "of paramount importance that public confidence is restored".
She made reference to 280 breaches of standing orders and "a complete breakdown in control at the top of the organisation".
The UUP's Ross Hussey asked about the involvement of the Serious Fraud Office and the police.
Dr McPeake said matters relating to the Red Sky contracts had been reported to the police twice.
On both occasions the police decided that evidence did not exist to a criminal standard that would have warranted a fraud prosecution, he added.