Bank of New Zealand (BNZ) says it's losing two senior executives.

In a stock exchange announcement BNZ says chief operating officer Stephen Mockett left last Friday, August 12, and chief risk officer Martin Philipsen plans to step down.

"Philipsen will remain as chief risk officer until a replacement is appointed," BNZ said.

"Paul Suma has been appointed to the BNZ leadership team and will be responsible for the Office of the CEO (Andrew Thorburn) and the Bank’s strategy function."

The bank said Suma has extensive experience, including about 22 years in wealth management and private and investment banking, having worked for several financial organisations. He's currently the head of private clients for NAB Wealth, a unit of BNZ's parent National Australia Bank, covering New South Wales and the Australian Capital Territory.

"The appointment is subject to receipt of the necessary authorisation from the Reserve Bank of New Zealand. The Reserve Bank of New Zealand has been advised of these changes," BNZ said