It is understood that some of the files are in poor condition and cannot be read, while those that have been examined appear to be internal bank documents rather than loan applications or customer statements.
AIB officials are sifting through one-and-a-half refuse sacks of bank documents at the former Killacloyne landfill site near Glounthaune in east Cork.
Officials from AIB joined medical records staff of the Health Service Executive at the Killacloyne site this morning, as a contractor with specialist equipment sifts through tonnes of earth and waste.
It is understood that hundreds more documents have been uncovered. However, it appears at this stage that these relate to HSE medical records.
In April, confidential medical files of hundreds of people were uncovered at the same site.
They contained the names, addresses, dates of birth, medical conditions and treatments of people who attended a number of Cork hospitals from the 1970s to mid-1980s.
The Health Service Executive has sealed the site, initiated an investigation and promised to recover any other files which were buried there.
The AIB documents were discovered while a contractor was sifting through material at the site searching for other medical files.
The bank has confirmed that an investigation is under way.
She said the offices of the Financial Regulator and Data Protection Commissioner would be informed of the discovery 'as appropriate'.
Data Commissioner Billy Hawkes told RTÉ News he would be concerned if confidential financial information was dumped in this way.
A spokeswoman for the Financial Regulator said it has repeatedly stressed the need for financial institutions to have adequate systems and controls in place to protect client confidentiality.
