The Ministry for Primary Industries (MPI) says its fishery officers have released 650 illegally caught pāua back into the sea after a compliance operation in Taranaki.
MPI said the operation was part of regular compliance checks across the region to make sure people were keeping within the rules "so current and future generations can continue to gather and enjoy this kaimoana".
The team issued eight infringements and nine warnings, and made one arrest.
In addition, several vehicles were seized, one person was arrested after obstructing a fishery officer who was trying to inspect their catch, and six people may face prosecution.
MPI's team manager of fisheries compliance for the western North Island, Andre Espinoza, said during the week-long operation, eight fishery officers interacted with around 180 people during patrols that took place at low tide.
"Most people understand that the rules are there for a reason and play an important part in looking out for our fisheries.
"We're grateful for the support we get from the community who share our frustration at the minority who want to break the rules. But there are still a few opportunists out there who take more than their daily limit or gather undersize pāua.
"We do not tolerate this type of offending, and people who want to take illegal pāua should know it could land them with instant fines ranging from $250 to $500, or see them prosecuted and their vehicles seized."
MPI said it encouraged the public to maintain vigilance and report suspicious fishing activity through its 0800 4 POACHER line – 0800 47 62 24.
• Check the fishing rules in your area here.