New Zealand’s Accident Compensation Corporation has started to refund about $NZ100 million ($91.57 million) in overpayments collected from more than 300,000 businesses dating back to 2002.

The national no-fault accident injury insurer discovered the mistake while preparing to switch to a new levy system.

“We very much regret the overpayments and apologise to anyone who made a payment that was not required,” Head of Business Customer Service Delivery Phil Riley said.

“Our focus is now on making this right as soon as we can, and we have already begun contacting affected customers.”

The $NZ100 million refund accounts for 0.37% of levies collected during the affected period.

It includes $NZ36 million ($32.96 million) from 106,000 self-employed customers and $NZ64 million ($58.6 million) in provisional invoices to 200,000 businesses that were not required to make the payments.