The Australian government has urged Japanese whalers and protesters to abide by international law in the wake of a reported clash in the Southern Ocean.
Environment Minister Greg Hunt is seeking information about claims the Japanese whaling fleet attacked activists in the Southern Ocean after dark on Sunday.
Environmental group Sea Shepherd says two Japanese harpoon ships attempted to disable its vessel The Bob Barker on Sunday night by trying to jam its propellers and rudders with steel cables.
The ships also repeatedly crossed the bow of The Bob Barker at close range, violating the International Regulations for Preventing Collisions at Sea, the group says.
But 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.
Mr Hunt says there are conflicting reports about the incident, and he is seeking additional information about the stand-off.
"My message is very clear to all parties - all sides must absolutely abide by international maritime law," he told reporters in Canberra on Monday.
Sea Shepherd says The Bob Barker was sailing six nautical miles behind the fleet's factory 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 breached international law.
But Institute for Cetacean Research(ICR) 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 as pirates by the United States Court of Appeals.
It is the second time this month the activist group claims it has been attacked by the whalers.
Mr Hunt ordered an investigation into earlier claims a Sea Shepherd vessel was rammed by the whalers in New Zealand waters on February 2.
Sea Shepherd chairman Bob Brown said the group felt let down by the Australian government because it had failed to live up to its promise to place a surveillance vessel in the whaling waters.
"The Sea Shepherd is doing the best it can to try to keep the law upheld from a civilian point of view but it's high time the federal government was down there and stopped the slaughter," he said.
