Japanese whalers have suspended their Southern Ocean hunting a day after their ships jostled with vessels from the radical anti-whaling group Sea Shepherd.



The organisation claims two of its ships were "rammed" yesterday by the Japanese factory ship Nisshin Maru as it tried to come alongside a Korean tanker Sun Laurel to refuel.



One of the organisation's ships, Bob Barker, sustained wheel house damaged and briefly issued a mayday distress signal fearing it might roll.



Video and photos released by Sea Shepherd confirm Nisshan Maru and Bob Barker collided but it is less clear whether it was a deliberate ramming.



Nisshan Maru appears to be coming alongside Sun Laurel as Bob Barker blocks the way.



Japan's Institute of Cetacean Research told the Australian Broadcasting Corporation that it had temporarily suspended the whale hunt.



It said the decision was made because it was too difficult to refuel.



Sea Shepherd's Paul Watson said Nisshan Maru's captain "lost his temper, and unfortunately road rage with an 8,000 ton ship in remote waters amongst icebergs and ice packs can be somewhat intimidating".



Watson said the 8000 ton Nisshan Maru also hit its own supply tanker four times.



The refuelling operation was planned for yesterday but the three Sea Shepherd ships, the Sam Simon, the Bob Barker and the Steve Irwin, had taken up positions around the Sun Laurel to block any approach by the Nisshin Maru.



Watson said yesterday morning the Nisshin Maru moved closer to the stern of the Sun Laurel as the three Japanese harpoon vessels began to circle with their water cannons shooting towards the Sea Shepherd ships.



"The Nisshin Maru kept edging closer in an effort to intimidate the Sea Shepherd Ships and it was indeed intimidating," he said.



"The Nisshin Maru towered above our ships at ten times the size."



Watson claims the bosun on Sun Laurel warned the factory ship to stop because they were dangerously close, but the factory ship continued to move closer, pinching the Steve Irwin between its massive hull and the side of the tanker.



The Bob Barker then moved into position to defend the Steve Irwin and attempted to block the Japanese poaching ship.



Watson said crew on Nisshin Maru were throwing "concussion grenades" and hitting both the Bob Barker and the Steve Irwin with powerful water cannons.



"At 12:56 Hours, the Nisshin Maru came up behind the Steve Irwin, hitting the Sea Shepherd vessel twice, once on the port stern, and again on the port side, damaging the helicopter deck and pushing the Steve Irwin towards the Sun Laurel," Watson said.



Bob Barker moved to allow the Steve Irwin to get out of the way of the Nisshin Maru.



As Nisshin Maru tried to cut off Bob Barker it hit the tanker's stern.



"They hit it four times, crushing a liferaft and damaging the davit in for their primary lifeboat," Watson said.



"They also inflicted damage on the Sun Laurel's superstructure and hull."



Nisshin Maru continued to hit Bob Barker.



"The monkey deck was buckled and the helicopter deck twisted as the Bob Barker's engineers reported water pouring into the engine room," he said.



Nisshin Maru backed off when they heard Bob Barker issue a distress call and the Bob Barker immediately began damage control.



The flow of water was halted within 15 minutes and the engineers brought power back on within a half hour, giving the ship the ability to get underway. The radar and starboard running lights were destroyed.



Watson said the news of the suspension of whaling by the institute was the best news of the day.



"It may well be over for this season, and hopefully we will not have to return next season if the Japanese whalers decide to finally respect the integrity and the sanctity of the Southern Ocean Whale Sanctuary."