Minister for Finance, Michael Noonan has confirmed that the number of customers involved in Ireland's tracker mortgage scandal is higher than the original estimate of 8,500.

According to the Minister, Central Bank governor Philip Lane believes that as many as 15,000 policy holders may be involved.

The Limerick City TD described the actions of these banks as "outrageous."

"I think it is important to put on the record as well that the Central Bank has statutory reporting obligations to An Garda Síochána and to other agencies where it suspects a criminal offence may have been committed by a supervised entity," he continued.

Sinn Fein Finance spokesperson Pearse Doherty has said the tracker mortgage scandal should be considered a criminal matter and that the bankers that oversaw the removal or denial of tracker mortgages should be "investigated for common theft."

He commented, "Today, we heard the usual refrain from Minister Noonan that this is a matter for the Central Bank. This scandal is much too important for that attitude to prevail. It is time for the Minister as the major shareholder in two of the banks involved to start asking questions about what happened at those banks under his watch.

"It is not too much to ask that the Minister ask questions about what was going on at banks he is the major shareholder in. It is also time for a criminal investigation into the theft of thousands of families’ hard earned money."

He added that, "Like any other theft, it is the State’s criminal investigators that must be involved in holding those responsible to account through the legal process not some obscure and secretive Central Bank investigation. A bank is a building, it was bankers that oversaw this scandal and it is bankers that should be investigated."

Fianna Fáil finance spokesman Michael McGrath also expressed his concern: "This is a scandal. This is disgraceful treatment of mortgage customers, Minister, and the Central Bank is going to have to fully exercise its statutory powers in this respect to ensure this issue is comprehensively dealt with," he said, according to The Irish Times.

15 lenders are involved in the industry-wide probe into cases when customers were moved off of tracker rates.

Tracker mortgages are set at a fixed percentage or 'margin' above the ECB rate. As its rates plummeted during the financial crisis Irish customers' rates should have dropped to close to 1%.

Affected customers are expected to get compensation of close to 15% of the savings that they missed out on by being denied these rates.