Tensions between anti-whaling protesters and the Japanese whaling fleet in the Southern Ocean have turned violent again.
Both sides are blaming each other for a collision in the early hours of Saturday morning between conservation group Sea Shepherd's boat Bob Barker and a Japanese whaling vessel.
In a written statement, Japan's Institute of Cetacean Research accuses the protesters of ramming its boat as they tried to shoot bottles containing butyric acid at the mother-ship.
However, Sea Shepherd spokesperson Bill Watson says the Japanese boat intentionally bore down on the Bob Barker, ripping a hole in its hull just above the waterline and endangering the crew.
He says the Sea Shepherd crew use butyric acid - non-toxic rancid butter - to make the whale meat inedible and halt what they believe is a commercial operation.
Its vessel has been repaired and no-one was injured in the incident.
The New Zealand-registered Sea Shepherd boat Ady Gil sank last month following a collision with a ship from the Japanese whaling fleet.
Australian reaction
In Australia, the Greens and the federal opposition are calling on the government to send in the navy to make sure no lives are lost.
"I'm really concerned that people may be killed in the clashes occurring," Greens leader Bob Brown told reporters in parliament house on Sunday.
"The Australian government's totally absent and that's irresponsible ... the presence of a surveillance ship will lower the tempo and make it safer."
Opposition environment spokesman Greg Hunt said Australia should send a ship to monitor events.
A spokesman for Environment Minister Peter Garrett said the government was not planning to take action over the incident.
The government ordered the Australian Maritime Safety Authority (AMSA) to investigate the collision involving the Ady Gill on 6 January.
Mr Garrett's spokesman said that investigation was ongoing.
It's not known if AMSA has interviewed the Japanese whaling crew involved.
Before the last federal election, Labor promised to take international legal action against Japan to stop the whaling, but no action has yet been started.
Senator Brown said Mr Garrett was "missing in action" on whaling.
"He hasn't been a disappointment, he's been a complete failure," he said.
