A government agency has laid charges against the skipper and factory manager of a Korean fishing boat, alleging they misreported their catch and illegally dumped fish at sea.

The Ministry for Primary Industries on Wednesday said it had laid the Fisheries Act charges against the pair from the Oyang 77 in Christchurch District Court.

Eight charges were laid against the skipper and three against the factory manager. Dumping fish carries a maximum fine of $250,000.

It is understood the men are back in South Korea, with which New Zealand has an extradition treaty.

Ministry deputy director-general Scott Gallacher said it only laid charges when there was sufficient evidence to prosecute.

"The New Zealand fishing industry has a good level of compliance with regulations, but breaches like this do occur from time to time."

Earlier this week 3News showed footage it said was of the alleged fish dumping, including a basking shark that was caught by mistake and allegedly never reported.

Oyang 77 is a sister ship to Oyang 70 which sank off Otago two years ago, killing six, and of Oyang 75, whose crew walked off in Lyttelton in protest at inhumane conditions.

The ship is chartered by Southern Storm Ltd, a Christchurch-based shell company for Korea's Sajo Oyang Corporation.

Southern Storm's lawyers, Nelson-based Ocean Law, would not comment when contacted.