A fisherman targeted in an investigation into dumping has admitted that what he was doing was illegal, but says he was never charged.
Wayne Eden's boat Te Tonga was one of five vessels video footage shows were dumping or not reporting fish in an investigation off Timaru and Oamaru three years ago.
The revelation that no one was prosecuted has pressured the Ministry for Primary Industries into ordering an independent inquiry.
The leaked report into Operation Achilles noted that Wayne Eden's vessel was only very reluctantly entered into the electronic monitoring survey, and when cameras were installed, they were not turned on.
However, a ministry observer was on board, and the report said large quantities of fish were openly discarded in their presence.
Mr Eden, of Ashburton, told RNZ News his boat was "one that was dumping a lot of fish".
He defended that, saying they let go large, pregnant fish - but he also agreed that what they were doing was illegal.
Asked repeatedly if he had received any assurances from MPI that he would not be prosecuted, he said he needed to speak to his lawyer, as he had signed something at the end of Operation Achilles that he though might have been a confidentiality agreement.
Two other fishermen RNZ News approached said they wanted someone to blow the whistle on dumping, but that it was too dangerous to talk openly about it.
Auckland University fishing researcher Glenn Simmons said the new inquiry must range well beyond Operations Achilles, and Operation Hippocamp, a second MPI investigation that appeared to show a soft approach to dumping.
Dr Simmons is part of a collaboration between the University of British Columbia, Auckland and Oxford universities, whose report exposed decades of fish dumping and illegal practice.
"There's a number of investigation reports, and one that comes to mind is Operation Overdue back in 2004, involving carton weight fraud, where there were no prosecutions stemming from it despite a pretty intensive investigation," said Dr Simmons.
He said there were other reports since then worth looking into, though he would not put a number on it.
"You've only got to look at the tone of Operation Achilles to see they've known about it for many years."
Mr Simmons questioned why MPI's tests of on-board cameras, like during Operation Achilles, had been going on for 13 years with no real result.
Dr Simmons, told Nine to Noon the inquiry should be undertaken by a senior retired judge.
"It is important that the New Zealand government is seen to be going the extra mile.
"All the authors feel that the inquiry is too narrow - it needs to be wider - because we are aware of other reports that we've included in our catch reconstruction, and they should be also looked at."
The lobby group Forest and Bird wanted the new inquiry to look into that too.
"The vast majority of our fishing fleet ... doesn't have cameras or any observers," spokesperson Kevin Hackwell said.
"They historically have had incredibly low levels of observers. That's why we need to have the cameras on.
"The test in this case was very clear, that there was a huge amount of illegal activity going on in the boats."
But it was not prosecuted, and Kevin Hackwell said the inquiry must look into whether MPI had been giving fishermen assurances they would not be prosecuted.
MPI has said it did not have enough evidence to prosecute, and added the information from Operation Achilles had resulted in far stronger measures being put in place.
Mr Eden is still fishing. Asked if dumping was going on in the same way today as in 2013, he said it had changed a little, but would not elaborate whether it was for better or worse.
The leaked report from three years ago showed between 20 and 100 percent of some quota fish were being dumped every haul.
Labour Party fisheries spokesperson Rino Tirikatene said MPI was an embarrassment and could not be trusted.
"What it shows though, is that had these reports not come to light, to the public, we would have been none the wiser," he said.
"It begs the question, you know, how many other investigations or what other activities have been lurking within MPI that have been suppressed."
MPI director-general Martyn Dunne said it was a high priority that the ministry be seen by the public to be holding lawbreakers to account.
The inquiry's terms of reference, and the Queen's Counsel who will undertake it, will be outlined in due course.