A recently released email shows the Ministry for Primary Industries (MPI) did not want to prosecute fish dumpers for fear it would jeopardise future operations.
Prime quota species being thrown overboard has been caught on camera by MPI. It's blatantly illegal behaviour, but MPI decided no one should end up in court.
"The way in which the decision not to prosecute over the apparent dumping of quota fish is regrettable," says MPI Director General Martyn Dunne.
"It is also very disappointing that the process was characterised by confusion and a lack of adequate documentation and communication."
The case for a prosecution was made clear in a 2013 MPI report called Operation Achilles. The purpose of the operation was to put observers and cameras on vessels to monitor dolphin by-catch.
When investigators also filmed illegal fish dumping, they recommended a prosecution.
But that never happened, and an email that has just been released explains why.
"My concern is that prosecuting these fishers where there seems to have been implied immunity could potentially scuttle this very important project," it read.
It means they feared punishing those who volunteered, which could make it difficult to get by in the future.
"This is supposed to be the agency that enforces the law and the senior managers of that agency blocked prosecution, even though they were sitting on evidence that showed flagrant, systemic fish dumping," says Greenpeace Executive Director Russel Norman.
The author of the email was MPI's Director of Fisheries, Dave Turner - but he gave Newshub a different explanation for not prosecuting in June this year.
"We couldn't prosecute because of the legislation - we couldn't use the evidence gathered by the video footage," he said at the time.
The Independent Investigator investigating the case says the decision to not prosecute was "flawed" in that the law simply wasn't enforced.
"Mfish and MPI, in my view, have not grappled effectively with aspects of the problem, and neither enforced the law or acted to change it," says Michael Heron QC.
The QC's inquiry was initiated after a Newshub investigation, which involved the public release of Operation Achilles.
MPI's own investigator stated in that report that five of six vessels monitored openly dumped fish - between "20 to 100 percent of some quota species were discarded during every haul".
Two months after that was revealed, out came two emails from MPI sent to all staff, and Scott Gallacher and Andrew Coleman had both resigned - although the boss claims that's got nothing to do with the failure to prosecute.
"It is a coincidence," says Mr Dunne.
The recreational sector says an overhaul of MPI is necessary to restore public confidence.
This review was undertaken because MPI's credibility was under attack, but the findings have done little to restore that.