A University of Otago professor is calling for a review into the Ministry of Primary Industries fisheries quota management system.
In a statement, Prof Steve Dawson, of the department of marine science, said a "robust scholarly review'' of the system was needed.
His call comes after University of Auckland business school researcher Glenn Simmons released a paper saying half the fish caught in New Zealand waters do not show up in official records because they are dumped at sea or not declared.
The total catch between 1950 and 2010 was 38.1 million tonnes, the study says, compared with a reported catch of 14 million tonnes.
Mr Dawson said the study "formalises and quantifies'' what everyone has known about about fishing for years - that dumping and misreporting were rife within the industry.
He questioned MPI director fisheries management Dave Turner's response to the study.
Blaming fishers was not the answer, Mr Dawson said.
"The dumping and hi-grading problems arise because the quota management system provides incentives to do so. With quota so limited and valuable, there's a strong temptation to dump fish that are undersized or damaged or the wrong species so that fishers can maximise their return from a limited quantity of fish,'' Mr Dawson said.
MPI's questioning of the data was "curious'' as much of the data was gathered government agencies or former MPI employees, he said.
"MPI's reaction to the report is a sadly predictable case of shooting the messenger. It would be so much better if they concentrated on fixing the problems.''
On Monday, in response to the study, Mr Turner said an initial review of the report raised concerns about methodology and conclusions.
"We are clear the report simply can't draw adequate conclusions about sustainability ... because the measure of sustainability is abundance ... not extraction as the report attempts to analyse.
"We have decades of peer-reviewed science that shows steadily increasing levels of abundance,'' he said.