Thousands of insurance customers could be in for refunds.
A Financial Markets Authority and Reserve Bank review's found many insurers hadn't been doing enough to ensure products are suitable, and are overcharging some customers.
In some cases, they double-charged customers, hadn't given multi-policy discounts, or significantly overcharged premiums, because of poor IT systems.
Financial Markets Authority director of banking and insurance Clare Bolingford told Kerre McIvor those insurers could be issuing refunds.
“They've reviewed their products and realised that some mistakes have been made and some errors have been made. They are going through all their systems and making sure their customers get recompensed where they've been overcharged or where discounts haven't been applied.”
The Insurance Council says companies have been working proactively to address areas of concern.