The federal government's inaction on whaling has been likened to bushfire fighters coming across arsonists armed with flame-throwers - and being told to do nothing.
Bob Brown, former Greens leader and chairman of activist group Sea Shepherd Australia, says a clash between the Sea Shepherd vessel, the Bob Barker, and Japanese whalers on Sunday amounts to brigandry.
Sea Shepherd says its ship was deliberately struck by the Yushin Maru No. 2 in the Southern Ocean, in retaliation for the group preventing any whales from being captured for more than a week.
Federal Environment Minister Greg Hunt has ordered an investigation into the claim.
Mr Brown says that isn't good enough.
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"We get the Abbott and Key governments waggling their distant fingers at both sides and calling on everyone to take it easy," Mr Brown said in a statement.
"That's like the Volunteer Bushfire Brigade coming across a mob of arsonists with flame-throwers and the ministers calling on them to leave each other alone.
"Either these governments support whaling or they oppose it. If they oppose it they should get down to the International Whale Sanctuary and stop it."
Mr Hunt said while the alleged incident occurred in New Zealand waters he had ordered an investigation and briefing on the matter.
"This must be a message to both parties - whalers and protesters - these are dangerous waters, nobody can play any games with safety, nobody can play any games with international maritime law," he told ABC radio.
"Everyone must abide by the law and of course if there is evidence that either party has breached international maritime law, we will raise it."
The commercial hunting of whales is banned in the Southern Ocean Whale Sanctuary, but Japan catches the mammals under a "scientific research" clause in the moratorium.
Comment is being sought from the pro-whaling Institute of Cetacean Research.
