The ASB investment adviser has now offered to help the bank and the Serious Fraud Office to prevent other rip-offs, the Sunday Star Times reported.
Versalko, 52, was last week jailed for six years for running a scam in which customers' money was supposedly placed in high-yield investments, but was in fact siphoned off to fund a lavish lifestyle which included extensive property purchases and millions spent on prostitutes.
But in a letter to ASB chief executive Charles Pink on March 16, two days before his sentencing, Versalko said he wanted to help the bank "in any way possible".
"The years ahead are going to be very difficult, however I want to make amends even if only in a small way," he wrote. "My concern is that anyone could have committed the offence.
"It was easy for me to disguise my fraud and I would like to assist you and the Fraud Team at ASB to prevent this happening again."
In another letter, to the Serious Fraud Office, Versalko offered to be of service to the agency. A source close to the investigation said Versalko's offer was unlikely to be accepted.
In a statement made after Versalko's sentencing, ASB said changes had been made to "further strengthen" security. An SFO source was dubious of his claims the system could be manipulated by "anyone".
"[Versalko] was senior and in a position where he was authorised to make transactions over a certain amount," the source said.
Despite Versalko's fall from grace many friends and relatives have supported him, including his wife Megan.
"I'm trying to get on with my life," she told the Herald on Sunday.
Since the revelations of her husband's fraud, she had had to find a full-time teaching job, and sell her home and move into rented accommodation.
Court documents contain an interview in which Versalko said that while brother Greg had agreed to stand by him, another brother, Andy, was "aggrieved".
Andy's wife, Andrea Versalko, described Versalko as "a slug who should be squashed".
Versalko's children, university students aged 22, 20, and 18 had hidden their Facebook profiles and changed cellphone numbers to avoid media.
