Anti-whaling campaigners and Japan have engaged in a fresh war of words after a Sea Shepherd ship clashed with Japanese whalers in the Southern Ocean.
Japan asked the Netherlands to take measures against the Dutch-registered Bob Barker after it collided with a Japanese whaling ship.
In Tokyo, chief cabinet secretary Yoshihide Suga condemned environmental group Sea Shepherd.
"The sabotage activity was extremely dangerous," Suga told reporters.
"It is unforgivable.
"As a government, we are asking the Netherlands, where the ship is registered, to take practical measures."
Sea Shepherd says its ship was deliberately struck by the Yushin Maru No.2 in retaliation for the group preventing any whales being captured for more than a week.
Australian Environment Minister Greg Hunt has ordered an investigation.
Bob Brown, former Greens leader and chairman of Sea Shepherd Australia, says that isn't good enough.
"We get the Abbott and (John) 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 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.