A Korean fishing company is paying private investigators to find out how academics and the Sunday Star-Times obtained information on the slave-like conditions aboard foreign fishing vessels.

The Sunday Star-Times can also reveal:

- Private investigators followed the US ambassador on human trafficking, Luis CdeBaca, when he met university academics and a Fairfax reporter in Auckland.

- Academics were directly confronted after going on to meet crew from the Korean vessel Shin Ji, which had been fishing for eel until crew walked off in protest at abuse.

- A Fairfax car, parked on private property, was broken into. Equipment and a credit card were left behind but a hands-free kit that logs telephone calls was taken.

- That the Sunday Star-Times has asked the ombudsman to intervene after Maritime New Zealand sought $3040 for files requested under the Official Information Act relating to foreign vessels.

- That an executive at the Oyang Corp fishing company admits its lawyers hired investigators "looking for, and now finding" where information was coming from. The official identified a specific reporter – "he is a very dangerous one".

The private investigators have targeted Auckland University Business School academics, who will this week release a report on human rights abuses suffered by 2000 men from 27 foreign fishing boats in New Zealand's exclusive economic zone.

The report focuses on the deaths of six men in the 2010 sinking of the Oyang 70, which went down 650km off Dunedin while fishing Maori iwi quota.

Oyang, part of Korea's giant Sajo Group, says it cannot afford to pay New Zealand minimum wages to crews – although it tells government officials it is doing so.

"If we pay like the Kiwi, our business cannot survive. That is why we have to invite in Indonesian crews," an official said.

The company claims it is losing millions while the Oyang 75 – brought in to replace the 70 – is tied up in Lyttelton, with its Indonesian crew refusing to work.

In the university study, lecturer Dr Christina Stringer, PhD candidate Glenn Simmons and fisheries consultant Daren Coulston interviewed crews and families in two Asian countries, obtaining dozens of files under the Official Information Act.

They also have documents showing that New Zealand officials are routinely lied to over wages and conditions. They found foreign vessels engaged in illegal dumping and high-grading – throwing quota and by-catch overboard in the hope of higher-value catches later.

The business school's study shows crews are routinely exploited by fishing companies and the agents who hire them in Indonesia, the Philippines and Vietnam.

It includes statements from sailors and witnesses exposing what goes on, including one from a man who described officers as "vicious bastards", detailing an assault that split a man's head.

"I told the master, can't leave him cause he's bleeding all over the squid. He said, `oh no, no, he's Indonesian – no touchy, no touchy'. I took him to the bridge and third mate said, `Indonesian – no stitchy, no stitchy'. I ended up giving over 26 stitches." There are also details around foreign officers sexually abusing Indonesians at sea.

The Sunday Star-Times reporting on the industry last month forced Fisheries Minister Phil Heatley and Labour Minister Kate Wilkinson to launch a ministerial inquiry.

The scale and detail of the findings emerging from the study have alarmed government and fishing industry officials.

The authors say they found "disturbing levels of inhumane conditions" on board foreign vessels. The practices had become institutionalised.

In the past, crews protesting conditions have been deported but publicity in the cases of the Oyang 75 and Shin Ji has prevented that.