The Financial Markets Authority (FMA) has filed criminal proceedings against an individual connected to Heartland Bank for insider trading.
The regulator alleged the individual traded and encouraged others to buy or hold shares in the bank's parent company, Heartland Group Holdings.
It said the events took place when the person was a junior employee at the bank in 2020 and 2021.
The FMA claimed the person also disclosed information that was not available to the public to others.
Heartland Bank confirmed the former employee appeared in the Auckland District Court on Tuesday.
In a statement, the bank and Heartland Group Holdings said they were not parties to the court case and have cooperated with the FMA in its investigation.
"We take our responsibilities as a listed company very seriously. That includes having policies and procedures in place to ensure directors and employees at all levels understand their obligations under insider trading laws."
The law prohibited people with special information about a company from disclosing it or advising others to trade in the company's shares.
The FMA said unethical trading can undermine the market and breach investor confidence.