Throughout his tenure, Clyne led over 42,000 NAB employees, and is credited for helping the bank stay strong during the global financial crisis. In a statement, he said that he is leaving the company as a "strong, customer-focused bank."

Thorburn was previously the CEO of Bank of New Zealand, a subsidiary of NAB, where he worked since 2008. He also served as an executive general manager for retail banking at NAB for three years. Prior to that, he was group executive, personal customers at St George Bank and held a number of senior roles at the Commonwealth Bank/ASB Bank Group. 

His replacement at BNZ will be announced in due course.