More than $500,000 has been refunded to car owners whose vehicle's safety was wrongly classified by ACC.
Changes this month saw different car models categorised based on how safe they were, with lower levies for safer cars.
But a system glitch overcharged 18,000 people, and ACC Minister Nikki Kaye is calling it a teething problem.
"This is a new system. Those data errors have been fixed," she told RadioLIVE.
"We will be making sure that we have a motor vehicle advisory group to look at any further changes in the future."
She says Labour's claim the glitch cost $6 million is wrong.
Labour ACC spokesperson Sue Moroney yesterday said as many as 90,000 vehicles may have been wrongly classified, with 23 models affected.