BNZ bank has been given a warning by the Commerce Commission after it admitted to possible breaches of the Credit Contracts and Consumer Finance Act.
In late 2018 BNZ alerted the Commission to 15 matters relating to home and personal loans, credit cards and overdrafts entered into by 11,956 customers between June 2015 and February 2017.
The Commission said BNZ likely breached responsible lending and disclosure obligations under the Act.
"For example, in some cases BNZ provided incomplete or inaccurate disclosure, and in other cases disclosure was provided a day, a few days, or as many as seven months after the information should have been provided to borrowers," Commerce Commission Chair Anna Rawlings said.
"We expect lenders to regularly audit their systems to make sure that they can comply with consumer credit law, or quickly identify problems if they arise, fix them and provide appropriate remediation to borrowers."
At the time the potential breaches were reported, BNZ refunded about $3.8 million to affected customers, and an additional $1m in September this year.
Rawlings said BNZ has co-operated fully with the Commission.
"BNZ has identified these matters itself and reported them to the Commission, made remediation payments to its customers and made system changes to reduce the risk of issues like this arising in the future.
"Taking into account those steps, and consistent with our Enforcement Response Guidelines, we have decided that it is appropriate to issue a warning to BNZ for this conduct."