The Reserve Bank has confirmed that former deputy governor Geoff Bascand left the bank a week earlier than agreed to over a breach of protocol.
The central bank, responding to a National Business Review article, said Bascand disclosed that he had shared information about its leadership reorganisation to a third party, which was unauthorised and a breach of protocol.
Bascand, who was due to depart in early January, agreed to bring forward his planned leaving by a week.
"Mr Bascand apologised for his actions and accepts it was a lapse in judgement. The Reserve Bank Board and the Minister of Finance have been informed," a bank spokesperson said in a short statement.
"The Reserve Bank will not be commenting on this matter further at this time."
The bank underwent a leadership reorganisation last year.
In December the bank announced that Sarah Owen, Kate Kolich and Greg Smith would become assistant governors.
"Their appointments are made following a robust recruitment process as part of the plans for the expanded and refreshed structure of the Reserve Bank's executive leadership team," the bank said at the time.
In October, the Reserve Bank announced plans to bolster its overall capability and capacity.
Bascand's resignation was made public on September 7.
Governor Adrian Orr said at the time that Bascand "leaves with the Bank's deep gratitude for his contribution to the Bank and the wider financial system".
"Geoff has made an incredible contribution to the Bank, and we're indebted to his leadership, guidance and wisdom," Orr said.
Bascand had been Deputy Governor with the Bank since May 2013, having previously served as Government Statistician and the chief executive of Statistics New Zealand.
He has worked for the New Zealand Treasury, the International Monetary Fund in Washington, and the New Zealand Department of Labour.