But it said “an independent forensic investigation” by accounting firm KPMG had “determined the most likely scenario was the tapes had been disposed of.”
It added “the tapes did not contain passwords, PINs or other data which could be used to enable account fraud”.
And it stressed there had been no evidence that customer information had been compromised, with monitoring mechanisms remaining in place.
The Commonwealth Bank’s acting head of retail banking, Angus Sullivan, described the incident as “unacceptable” and has apologised for any “inconvenience and worry” the incident may have caused customers.
Australia’s Treasurer Scott Morrison has warned that financial executives could face strong penalties, including jail sentences, from evidence brought up at the inquiry.