Japan has now temporarily suspended its annual whale hunt after anti-whaling group Sea Shepherd has accused the Nisshin Maru of ramming two of its vessels in an act of "road rage" as the protesters tried to prevent the whaler from refuelling, Australian Minister for Environment Tony Burke said in a ABC news program on Thursday.
The anti-whaling group Wednesday claimed two of its boats, the Steve Irwin and the Bob Barker, were rammed by a Japanese ship in Australian Antarctic waters, saying the attacks happened after they were ordered to leave the area by one of the boats in the Japanese whaling fleet.
It also claimed armed Japanese coastguards threw "concussion grenades" at activists on the ships.
Japan's fisheries agency has denied those reports, but confirmed that one of its factory ships, the Nisshin Maru, rammed two boats belonging to Sea Shepherd.
However, it said the clashes happened after activists came too close to a Japanese vessel which was refuelling.
According to local media reports, Japan's Institute of Cetacean Research has announced it has stopped work for the time being because it is too difficult to refuel.