KEY POINTS:
Anti-whaling campaigners have endangered a Japanese whale boat crew and scientists by throwing bottles of acid and ramming their vessel in the Antarctic, Japan's whale research body said.
The Institute of Cetacean Research in Tokyo said the Dutch-flagged protest vessel Steve Irwin launched an attack on the whale-spotting vessel Kaiko Maru on Friday night, just after it had completed a day of research.
The ICR said protesters from the Steve Irwin threw about 15 bottles of acid and bottles containing a bluish-green liquid at their vessel.
The US-based environmental group said the Japanese ship, the Kaiko Maru, was spotted north of Mawson Peninsula.
"The crew pursued and delivered 10 bottles of rotten butter and 15 bottles of a methyl cellulose and indelible dye mixture," said the statement.
"That is one stinky slippery ship," the protest boat's Peter Hammarstedt said.
The Japanese Fisheries Agency said no one was hurt and the Japanese vessel was not damaged during the incident which lasted about three hours.
Japan's whaling fleet is in the Antarctic for an annual hunt. Despite an international ban on whaling, Japan justifies the hunt on the grounds this whaling is for "scientific" purposes.
Much of the meat ends up on supermarket shelves.
The Japanese agency also accused the Steve Irwin of engaging in several hours of dangerous close harassment and of ramming the Kaiko Maru.
However, the Sea Shepherd Conservation Society, which owns the Steve Irwin, accused the whaling boat of entering Australia's economic exclusion zone.
"I have a chart here and it clearly states that these waters are Australian EEZ," Steve Irwin's captain Paul Watson said on the Sea Shepherd website.
"There is an Australian Federal Court order specifically prohibiting these ships from whaling in these waters. We have informed the whalers they are in contempt of this court ruling."
He said their actions had severely disrupted the Japanese vessel's whaling activities in Australian waters.
ICR director Minoru Morimoto said the Japanese activities in the Antarctic were legal and described the activist group as terrorist vigilantes.
"Their activity threatens the safety of our crews and scientists and should not be condoned," he said.
The militant group is tracking the Japanese whaling fleet through heavy ice in Australia's Antarctic waters.
The Japanese whaling fleet plans to kill about 1000 whales this summer.
The Australian Government has appealed for calm on the high seas.
- AAP