Fishermen from the Korean-owned Oyang 75 have described being hit and seeing other crew members punched by their bosses during two trips to New Zealand waters last year.
Korean fishing officers Wongeun Kang, Juncheol Lee, Minsu Park, Tae Jo and Chong Yun are accused of illegally dumping up to 1000 tonnes of New Zealand quota fish valued at almost $1.3 million during the trips and of making false statements.
The accused have failed to appear at the Christchurch District Court.
Indonesian crew member Ahmed Tohir told the court on Tuesday the Korean officers were cruel and regularly hit him on the head whenever he did something wrong.
Mr Tohir said he also saw an officer punch another crew member who had accidentally bumped into him.
The vessel's cook, Sodikin, also gave evidence on Tuesday, saying the Korean officers used physical abuse and spoke roughly to the mainly Indonesian crew.
When questioned further, he demonstrated a vigourous summoning gesture with his arm and said the officers would say, "Come here dog".
Both Mr Tohir and Sodikin said they were ordered to dump New Zealand quota fish and felt they had to comply.
Sodikin said if he had not followed instructions, the consequences would have been severe. He believed he would have lost his job and been sent home at his own expense.