The Central Bank has revealed that at least 8,200 Irish mortgage account holders have been denied a tracker rate by their lender.

It said on Monday it expects that lenders will have "identified and commenced engagement" with those customers affected by the middle of next year, with more cases likely to have emerged by then and indications that the total number affected could top 10,000.

The regulator is currently examining the tracker mortgage scandal, looking at 15 lenders that offered these loans before the economic crash in 2008.

The largest such scandal in the history of the State saw many account holders denied a right to or option of a tracker rate of interest, or the correct rate was not given to them as per their contract.

The Central Bank's director of consumer protection Bernard Sheridan said in an investigation update that lenders are at different stages in the process through which they are required to stop charging the incorrect amount, review the customer's account and assess the compensation due.

He said:

"The Central Bank continues to challenge all lenders to ensure that they identify all impacted customers in a timely manner."

Permanent TSB was the first lender revealed to be involved. Though it initially challenged a finding that it had stopped borrowers from legitimately reverting to tracker rates, it withdrew a Supreme Court appeal in February 2015 and began its redress programme.

Appearing before the Oireachtas finance committee today, Central Bank Governor Philip Lane said that there have been "far too many cases" of borrowers being denied tacker rates. 

He said:

"This is absolutely unacceptable, and it is the reason why we decided that a broader examination of tracker-related issues was warranted and why we are ensuring such a comprehensive examination is being undertaken.

"Let me assure you, the Central Bank will take all necessary action to hold regulated firms and individuals to account for failures in relation to tracker mortgages. The process we are overseeing is exhaustive but takes time."

Lane also told the committee that banks have been using league tables to incentivise staff to drive lending without taking care that it is of quality. He said inspections have shown that there is a need for "better oversight and challenge" from boards in relation to the risks banks are willing to take.