Confrontation in the Southern Ocean has led both the Japanese whaling fleet and Sea Shepherd to claim to be the targets of deliberate collisions.
A video of the latest incident on Monday afternoon, is now posted online.
Sea Shepherd founder, Paul Watson claimed the Nisshin Maru, a Japanese factory ship, rammed one of its vessels, the Bob Barker, twice on Monday afternoon, causing it to collide with a tanker, the Sun Laurel.
However, the Institute of Cetacean Research, said Sea Shepherd vessels sabotaged the Nisshin Maru's refueling, ramming their vessels at least five times.
A Japanese icebreaker, Shirase, has now arrived to assist the whalers.
The Cetacean Institute says the refueling operation is essential for the safe navigation of ship.
It said the attack by Sea Shepherd was not only malicious but threatened the safety of the ships and their crew.
Sea Shepherd last Wednesday claimed the Bob Barker and the Steve Irwin were rammed by the Nishin Maru.
Statement
In a statement to Morning Report on Tuesday, the Institute of Cetacean Research Centre said:
''Japan's research whaling in the Antarcticis a perfectly legal activity carried out under the International Whaling Convention for the Regulation of Whaling.
''This time, Sea Shepherd is sabotaging refueling operation, which is essential for the safe navigation of ships, and the sabotage is not only malicious but inconceivably obstructive actions.
''Thus it threatens safety of our research ships and lives of crews on them and is therefore completely unacceptable.
''Over and over again, we call on all related countries including the Netherlands, Australia and New Zealand which are flag states and/or port Sea Shepherd vessels, and the United States in which (the)headquarters of Sea Shepherd is based, to take every measure available to restrain them and deal with their criminal actions in a strict and objective manner.''
