AAP


Japanese whalers have accused Australian anti-whaling activists of ramming its Nisshin Maru ship while it was trying to refuel in the Southern Ocean, but the Sea Shepherd denies any wrongdoing.


The whaling ship and a fuel tanker aborted a refuelling mission after allegedly being hit five times by the Steve Irwin, Bob Barker and Sam Simon vessels.


The Institute of Cetacean Research released a statement describing the Sea Shepherd's actions as "malicious" and claiming it had threatened the safety of the research ship and lives of crew on board.


However, Sea Shepherd director and former Greens leader Bob Brown told reporters on Tuesday he had footage showing the Bob Barker was legally preventing refuelling when it was "squeezed and bucketed" by the larger vessels.


"As it gets physically damaged by staying bravely in place to prevent this illegal operation from taking place, concussion grenades (are) exploding on the deck from the Japanese vessels," he said.


"Tokyo lies about its whaling operation being scientific and it is trying to pursue the lie that the villains down here are Sea Shepherd, when in fact it's criminal behaviour from the Japanese ships."


Dr Brown said the Australian government should intervene in the matter.


"It is time Canberra asserted Australia's legal authority to prevent this illegal whaling in Antarctica," he said.


The anti-whaling group has also accused Japan of sending a military icebreaker, the Shirase, to the Southern Ocean to defend the whaling fleet, but Japan denies the allegation.


Sea Shepherd director Jeff Hansen claims the Shirase is there to intimidate the activists.