The country's biggest bank is testing the powers of New Zealand's financial regulator in the High Court.
ANZ and the Financial Markets Authority appeared this morning in the Auckland High Court but the regulator says confidentiality orders prevent reporting much of what was traversed.
ANZ has brought a judicial review application and breach of confidence claim against the FMA over the extent of the FMA's powers.
The FMA has obtained bank records from ANZ and says it intends to disclose them to other parties for a consultation over an FMA investigation.
The FMA also intends to seek advice over possible action under a section of the law that lets the regulator sue on behalf of another person.