Commonwealth Bank chief financial officer Rob Jesudason has resigned after less than a year to become chief operating officer of the firm behind the world's fifth biggest cryptocurrency.

Mr Jesudason is returning to Hong Kong, where he was previously CBA's international financial services group executive, to become chief operating officer and group president of Block.one.

Block.one is the developer of the EOS token, which has a market capitalisation of about $US12.8 billion and is the fifth most valuable cryptoasset.

Bitcoin, the most valuable, is currently worth almost $US150 billion.

Mr Jesudason, who worked for JPMorgan and others before joining CBA in December 2011, has been replaced with immediate effect by Alan Docherty on an interim basis.

Mr Docherty was chief financial officer of CBA's Institutional Banking and Markets business.

"I am very pleased to have someone of Alan's calibre and experience step in to act as our chief financial officer while we complete an internal and external search for the role," CBA chief executive Matt Comyn said on Monday.

"We are making good progress with the renewal of the bank's executive team and I expect to provide an update on appointments to my leadership team in the coming weeks."

Mr Comyn is already looking for replacements for chief information officer David Whiteing, institutional banking and markets group executive Kelly Bayer Rosmarin, and human resources group executive Melanie Laing.

Mr Jesudason, who replaced the long-serving David Craig in June 2017, is understood to have told CBA of his decision on Friday.

Block.one chief executive Brendan Blumer said Mr Jesudason's skills were ideal for the tech-related role.

"Rob has a proven track record of success in global financial services, where he has been involved in industry innovation and facilitated regulatory advancement enabling the adoption of new technologies," Mr Blumer said.

"His alignment with our organisational priorities of creating compliant, high performance blockchain solutions, is an ideal fit for Block.one, and is an exciting conclusion to our thorough search for the right individual."