Fraud allegations, believed to involve several hundred thousand dollars, are being investigated at a Dunedin branch of one of the four major banks.
It is understood a female employee has been stood down over allegations of fraud over a long period.
Sources, who declined to be identified, said the alleged fraud may be in the range of $350,000 to $400,000.
The bank declined to comment.
"Our standard policy is not to comment on issues relating to fraud or alleged fraud," a spokeswoman said.
The bank regarded issues of fraud and fraud allegations "very seriously and we have internal processes and systems in place to address them", she said.
Detective Senior Sergeant Kallum Croudis, of Dunedin, said "no complaint had been laid with the CIB at this point".
