The organisation in charge of Japan's Southern Ocean whaling fleet is disputing allegations it attacked a protest boat, saying the fleet has a right to defend itself.
Environmental group Sea Shepherd says two harpoon ships crossed the bow of its ship Bob Barker 33 times at close range after dark on Sunday, dragging a 250m cable and a 150m cable across it in a bid to disable its propellers and rudders.
Sea Shepherd says Bob Barker was sailing six nautical miles behind the fleet's factor vessel Nisshin Maru in an attempt to block its slipway and prevent it from loading whales.
Bob Barker captain Peter Hammarstedt says its actions were lawful and the Japanese fleet's actions were a violation of the International Regulations for Preventing Collisions at Sea.
But Institute for Cetacean Research spokesman Glenn Inwood says the ICR doesn't agree with the Sea Shepherd's version of events.
"The Japanese vessels take defensive measures to protect lives and property from the Sea Shepherd group of animal rights extremists, who are operating outside of the law and are well resourced," he said in a statement.
He says Japan has a legal right to conduct whale research and that the Sea Shepherd has been referred to by the United States Court of Appeals as pirates.
