Australia's second-largest bank said McEwan would retire from executive roles and hand over the reins to Irvine, a British-Canadian dual citizen, from April 2. Irvine has been NAB's Group Executive Business and Private Banking since 2020.

Prior to joining NAB, Irvine was the head of Canadian business banking at Bank of Montreal. He also held a range of roles at BMO over more than 12 years.

Irvine would also assume the position of Australian banking association chair from McEwan on behalf of the bank.

"Andrew is well suited to take NAB into its next chapter of growth and performance for our customers, colleagues and the communities we serve," NAB Chair Philip Chronican said in a statement.

Irvine said in the statement that NAB was on the "right trajectory to being a better bank" and that he would work to continue executing its strategic ambitions.

McEwan's exit comes as heads of other leading Australian banks, like ANZ Bank CEO Shayne Elliott, are also considered likely to move on.

McEwan led NAB through four eventful years. He joined the bank in December 2019 with a mandate for change in the wake of a public inquiry into misconduct in the financial sector.

He also led the bank through the COVID-19 pandemic, which disrupted operations and triggered changes in banking systems globally.

NAB shares were down 1% at open, while the broader index was up 0.7%.

NAB reported a rise in its annual cash profit in November, as it benefited from elevated interest rates and an increase in lending and deposits.

(Reporting by Praveen Menon in Sydney; Additional reporting by Archishma Iyer in Bengaluru; Editing by Shilpi Majumdar and Stephen Coates)

By Praveen Menon