The Commerce Commission is seeking to introduce extra incentives to get firms and individuals to own up early if they are involved in price-fixing.
The regulator is revising its leniency policy on cartels and is seeking public feedback.
The commission says automatic conditional immunity from prosecution for those who first admit being part of a cartel, remains the main element in any successful enforcement plan.
But it is looking at adding a marker system, to encourage what it calls a race to be first through the door.
It also wants to follow other countries by offering to reduce penalties to those not eligible for immunity, if they provide information about separate cartel activity.
Submissions close at the end of the month.