Chinese authorities have deregistered and fined a Chinese commercial fishing company around $825,000, after captains misreported tuna catches.
Chinese authorities have found that the two vessels were not only unlicensed but that they misreported over 100 tonnes of high value southern bluefin tuna as another lower value species.
Southern bluefin tuna are listed as critically endangered.
It was the first time genetic samples of fish had been taken during an inspection by the Ministry for Primary Industries while at sea.
The penalties were for misreported catches, and fishing without a licence adjacent to New Zealand's Exclusive Economic Zone.
The ministry said HMNZS Otago picked up two fishing boats breaking international law in an area between New Zealand and Fiji.
MPI spokesman Gary Orr said as well as the company being fined and deregistered, its vessels had been permanently banned from all deep-sea fishing activities.