Accident Compensation Corporation board chair Paula Rebstock says employees and employers have not been paying too much in levies.
The corporation recommended a reduction in levies in the worker and earners account last year, but that was rejected by the Government. A reduction in both levies will happen in 2014.
Ms Rebstock appeared before a parliamentary select committee on Thursday morning.
Responding to questions from Labour, she said levy payers have not been over-charged in recent years.
Ms Rebstock said having extra money last year was useful as the corporation needed to put funds into making sure injury prevention and tightening privacy.