A “damning” report into the country’s fishing industry has revealed the number of fish caught is more than twice the number officially recorded.

Greenpeace says government officials were aware of the recording botch-up but instead of fixing it, the Ministry for Primary Industries “deliberately covered it up”.

For the first time a report in collaboration with Auckland University provides a reconstructed picture of New Zealand’s marine catches dating back to 1950 – it reveals while 15.3 million tonnes of catch was recorded up until 2013, an estimated 24.7 million tonnes had fallen through the cracks.

Commercial discards were estimated to be as high as 37.4 per cent of fish caught, according to the report.

Greenpeace executive director Russel Norman said the revelations were “explosive” and is calling for an independent investigation into the Ministry for Primary Industries (MPI).

He’s accused the ministry of looking after the fishing industry instead of caring for the oceans.

“New Zealand’s industrial fishing companies have been underreporting the number of fish they have been taking for years, and the evidence suggest the MPI has been covering for them,” he said.

But Minister for Primary Industries Nathan Guy disputes overfishing is still prevalent today.

“There may have been overfishing decades ago, but it is much harder for that kind of thing to happen now with observer numbers doubling in the last decade.”

“MPI takes a tough line on unlawful behaviour and has had 10 successful prosecutions since 2009,” he said.

The report shows MPI, in its own investigation, revealed it had been aware of the large-scale dumpings for many years – there were two reports done by MPI but neither were made public.

“This sort of information is damning,” Norman said.

“Not only has the catch been more than double what has been recorded, but it appears that MPI have known and kept it quiet,” he said.

Labour’s environment spokesman David Parker is also calling for an independent review of the country’s 30-year-old Quota Management System (QMS), which falls under MPI’s watch.

“The new fisheries catch data released today should be taken very seriously. It suggests a gross under-reporting of actual catch, which would mean a significant amount of by-catch is being discarded,” he said.

Lead researcher for the report, Glenn Simmons, said despite its intentions and international reputation, the QMS “actually undermines sustainable fisheries management by inadvertently incentivising misreporting and dumping.”

“A striking finding was the extent of misreporting to avoid…penalties.”

“This highlights a weakness of the QMS, which relies on full and accurate reporting, yet, in practice, incentivises misreporting,” he said.

While the QMS was an important step in “halting the rape and pillage era” in fisheries, it’s now in need of a “robust critical review”.

Guy said the QMS was considered “world leading” and New Zealand has been “recognised overseas numerous times…highlighting how our fisheries are sustainably managed”.

“The true measure of sustainability is fish in the sea and this report fails to address that.

“Overall our fishing stocks are in very good health and this is confirmed by in depth independent scientific research focussed on fish abundance,” Guy said.

However, one fisheries management official interviewed as part of the report, dumped fish is “really just an educated guess as the observer monitoring of most fisheries is limited, so discarded and undersize catch levels are not really known”.

Another officer suggested the profits of misreporting outweigh the penalties of being caught, while another industry member was quoted in the report saying, “if you don’t look for problems, you won’t find them”.

Norman said it was evident nearly “twenty per cent of all fish caught are stolen and over one third are thrown back”.

A fisheries’ insider quoted in the report said, “anything we don’t want goes over the side. A lot of the inshore boats I have been on just don’t even record what they throw over the side”.

Norman said the report explains why “average Kiwis are struggling to catch a fish for the dinner table”.

“The idea that almost every second fish is either stolen or biffed back into the sea dead as waste, goes against everything New Zealanders believe in,” he said.

2016 Fairfax New Zealand Limited