Two separate investigations are set to be launched over allegations that AIB misled financial regulators on the amount of progress it has made in dealing with impaired loans.

The claims have been made by a whistleblower who worked within a division of the bank that handles bad loans.

The individual suggested AIB has overstated progress on dealing with the loans, in order to suggest greater progress had been made in terms of restructuring the debts.

According to RTÉ, the whistleblower said restructures were "clustered at the end of each month and the end of each quarter, indicating the bank was under pressure to hit targets in advance of real progress".

AIB told The Irish Times it was "not aware" of the allegations which were made to both the Central Bank and the European Central Bank (ECB) in recent days.

The Central Bank said it could not comment except to confirm it received the allegation.

Allegations of this nature are made through a confidential email and are dealt with in a confidential manner.

It’s understood the relevant authorities within the Central Bank are to launch an investigation.

A spokesman for the ECB said it would not comment on an individual bank but it’s understood that allegations of this nature are investigated as a matter of course in order to establish validity.

Official sources in Dublin said the allegations would need to be fully probed by the Central Bank and the ECB’s regulatory arm, the SSM.

They pointed out that the area of the bank involved would have been overseen by a number of checks. These included the bank’s own internal audit, the annual external audit and regulatory oversight from both the Central Bank and the SSM.

The ECB can only investigate breaches of “relevant EU law”. These are laws that relate to the prudential supervision of banks, such as the laws on capital requirements and governance arrangements.

When an allegation of this nature is received, an expert team assesses whether it is relevant to the ECB or a national banking supervisor.

If, after the initial assessment, the expert team concludes that the report is relevant, it forwards the report to the responsible area within the ECB or to a national banking supervisor.

A supervisory action may be triggered, such as a request for information, an on-site inspection, the use of supervisory measures, or a sanction procedure.