News Hub reports it's the third time the crew aboard the HMNZS Hawea have caught offshore vessels breaking the law when it comes to proper disposal of waste.
The area is a multimillion-dollar tuna fishery - a precious resource that's often abused.
On board a Chinese long-liner, around 15km from land, the hold contains a sizeable catch of Albacore and Yellowfin Tuna, but it appears this haul matches the captain's books.
The vessel has a total of around 80 tonnes of fish on board, and the crew's documentation appears to all be in order.
