NAB chief Cameron Clyne to retire

Mr Clyne in a statement to the ASX on Thursday said it was time for him to retire.

"We have built a strong foundation for future growth with the revitalisation of the Personal Bank, grown our already strong position in business banking, and achieved material improvements in customer satisfaction and reputation."

"We have also worked methodically through our legacy issues while still making transformational change in our technology.

"I am leaving to spend some much-needed time with my young family. I am proud that I leave NAB as a strong, customer-focused bank."

One analyst who asked not to be named said that it was not surprising that Mr Clyne is leaving given NAB chairman Michael Chaney is also expected to exit next year when his contract expires.

"A new CEO will always have a different strategy, but Thorburn has been there a while so there is likely to be less uncertainty from shareholders," the banking analyst said.

Mr Clyne's tenure at NAB was "fraught with issues", having taken over the role during the financial crisis and having to deal with the problems of growing too fast in the United Kingdom and bad debts rising, according to the analyst.

Just last week, NAB confirmed that its struggling UK business would close 28 branches which it labelled "unsustainable''.

Mr Thorburn was appointed chief executive of NAB subsidiary BNZ in 2008 and his career in banking spans more than 27 years.