A legal glitch means the Government may not be able to prosecute commercial fishing vessels for dumping fish even if they are caught on camera, Primary Industries Minister Nathan Guy says.
As a result, the Government will consider changing the law to confirm that video evidence taken from fishing boats' cameras is admissible in court.
Earlier today, the Government committed to speeding up the rollout of onboard cameras on New Zealand's commercial fishing fleet, which are used to detect any illegal activity.
However, the Ministry for Primary Industry's lawyers have raised doubts about whether the video footage could actually be used to prosecute fishers.
As a result, Mr Guy said today that an amendment to the Fisheries Act could be required "to ensure that we can use these cameras for compliance reasons".
The problem became apparent last week when a 2013 Ministry for Primary Industries investigation called Operation Achilles was leaked to the public.
It showed that five fishing vessels were caught on camera dumping large amounts of healthy fish off the coast of the South Island, but no prosecutions were taken.
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Asked why the cameras had not been a deterrent to the dumping of fish, Mr Guy said: "This is where it gets very legal and very technical and that's why a QC has been brought in by MPI to have a look at whether they could get a prosecution or not."
On Thursday, the ministry launched a QC-led review of the Operation Achilles investigation, including the decision not to prosecute any of the fishers.
Mr Guy said the Government and MPI were disappointed that no prosecutions were possible in relation to the fish-dumping.
The legal obstacles do not extend to the popular Snapper 1 fishery, where all commercial fisheries already have cameras installed.
In that fishery, the ministry has signed a formal agreement which says that any video evidence can be used in court.
Operation Achilles also showed that two Hector's Dolphins - a relative of the Maui's Dolphin - were caught by one of the vessels. One of the dolphin deaths was not reported.
The dolphin deaths have spurred international environmental groups to urge companies, including fast food giant McDonalds, to stop sourcing fish from New Zealand.
Mr Guy dismissed the environmental campaign as "unfortunate" and "full of rhetoric". Hoki fisheries, which supplied McDonalds and others, operated at different depths to the Hector's and Maui's and were unlikely to catch the dolphins, he said.
The illegal activity reported in Operation Achilles was isolated, and would not damage New Zealand's reputation, Mr Guy said.
"We do have some ratbags in the industry, like any industry, and I expect the regulator to go very tough on them."
Government observation of commercial fishing operations
• 2003 - 2004: A Ministry of Fisheries investigation identifies that some boats are processing and reporting fish in a way which resulted in understatement of catch weights. A report is prepared for investigation.
• November 2012 - February 2013: MPI uses surveillance cameras on several fishing boats out of Timaru and Oamaru ports to observe the effects of commercial trawling on Hector's dolphins. Some suspected breaches of the Fisheries Act 1996 are observed. Ministry staff consequently undertake a more extensive review.
• February 2012 - March 2012: MPI undertake another operation to gather information to help determine information on catch mix and fish size.
• May 2016: Copies of the reports into the investigations are leaked, revealing the Ministry did not prosecute following the suspected breaches of the Fisheries Act.