The Reserve Bank has issued a formal warning to Westpac bank for failing to comply with anti-money laundering rules.
The central bank said Westpac's internal systems failed to detect and report almost 8000 corporate transactions to overseas recipients between July 2018 and February 2019.
The law requires financial service providers to report all overseas transactions worth more than $1000 to the police and the Reserve Bank.
There is no suggestion that Westpac was engaged in anti-money laundering activity.
Geoff Bascand, deputy governor and general manager of financial stability at the RBNZ said: "This formal warning reflects the importance of the prescribed transaction reporting regime in building an intelligence picture across New Zealand's financial system, and reiterates the seriousness with which we view non-compliance with the AML/CFT Act."