"We have tried to help customers transition from the passbook," Mr Comyn said at a Trans-Tasman Business Circle in Sydney.
Mr Comyn, who previously ran CBA's vast retail bank, said the lender had conducted research on trial offers designed to encourage people to switch away from passbook accounts. "And the research that came back was overwhelmingly: Do not do it."
In particular, Mr Comyn recounted one quote from a customer. "One of the verbatims which is always in my mind, from one of our customers .. was:" I hope I die before the Commonwealth Bank takes away my passbook, "he said.
"When you got customers preferencing death over the product or service, it feels like a pretty difficult area to go after," he said.
"I know I am very confident that we will continue to offer you books within the organization, not of standing of course there will be changes in other areas."
Mr Comyn recalled the idea in a wide-ranging speech that outlined how the bank planned to rebuild trust in the institution after a series of scandals.
Mr Comyn also announced that it was two apps.