The Data Protection Commissioner has said he was surprised at how widespread the practice of misreporting credit histories was among banks.
Billy Hawkes said he was also surprised at how long the practice had gone on for.
He said he was disturbed by the banks' misreporting because it had affected so many people who were already having financial difficulties.
The Office of the Data Protection Commissioner expects its investigation into all major financial institutions to be completed within a month.
But Billy Hawkes said he was expecting that the financial institutions were not waiting on his office to find the problems, and that they would have carried out their own investigations by now.
He said he also expected that those who had been misreporting had already taken the necessary action to correct the problems and notified the affected customers.
It was revealed yesterday from data audits at some of the country's banks that the credit histories of thousands of customers had been misreported to the Irish Credit Bureau (ICB).
The problems had been identified by the Office of the Data Protection Commissioner in customer credit records at more than one financial institution, including Permanent TSB.
The audits followed last August's admission by AIB that due to a systems error, it had over a six year period misreported the credit histories of 12,000 of its customers to the Irish Credit Bureau (ICB).
The ICB is a private company, owned by banks and financial institutions here, which collates customer credit histories on behalf of those banks.
The error at AIB involved the state owned bank sending incorrect details about customers missed repayments to the ICB, which resulted in the customers' credit histories looking worse than they actually were. This in turn may have impacted on the ability of the customers involved to access fresh credit. The ICB and the bank have since worked together to correct all the wrong data.
AIB's admission prompted the Office of the Data Protection Commissioner (ODPC) to begin a trawl of credit reporting systems at the other main banks here.
The ODPC would not comment on the detail of its findings so far. But a spokesman confirmed preliminary results indicate a need for a number of financial institutions to inform some customers that they have had their credit records categorised incorrectly by the Irish Credit Bureau. It is understood that several thousand customers are involved.
In a statement to RTÉ News, Permanent TSB has revealed that, following the revelations at AIB, but prior to the ODPC's audit, it initiated its own preliminary investigation which identified some errors in data supplied to the ICB.
The error involved incorrect reporting of missed repayments on certain loans which were being repaid weekly or fortnightly as opposed to monthly. The bank said that on becoming aware of the issue, it immediately notified the relevant regulators including the Central Bank, ODPC and the ICB and initiated a review which is now underway.
A spokesman for the bank said it apologised unreservedly for the problem and was taking immediate steps to resolve this issue and rectify the matter. The spokesman would not reveal how many customers were effected.
It is understood other institutions where audits have been completed by the ODPC include Bank of Ireland and National Irish Bank.
An NIB spokesman confirmed it had been audited last week but no results have been received yet.
A spokesperson for Bank of Ireland would not comment on the matter as it is also awaiting the ODPC's report. But sources at the bank said at this stage it appears no issues have been identified.
