Capt Watson said the Steve Irwin was now in pursuit of the Yushin Maru 2. "They have ceased whaling operations and they are now running from the Sea Shepherd crew," Capt Watson told AAP.

"If we can keep it on the run or shut down there's no whaling." He called on the federal government to order the whalers to stop the hunt. "The Sea Shepherd Conservation Society is officially calling on Australian Environment Minister Peter Garrett and Foreign Minister Stephen Smith to order the Japanese fleet to comply with the orders of the Australian Federal Court and to cease and desist from killing whales in Australian waters," he said in the statement.

During Saturday's encounter, Steve Irwin crew members attempted to throw rotten butter bombs at the Japanese vessel from a small boat, but blizzard conditions forced them back. "The winds were up to 45 to 50 knots and the waves got big and there were extremely hazardous conditions, so we called the boat back from doing that," Capt Watson said.

Capt Watson said his crew also planned to throw methylcellulose - a substance used as a gelling agent and a laxative - at the Japanese vessels. "I call it an organic, non-toxic biodegradable form of chemical warfare," Capt Watson said. Capt Watson said the Steve Irwin had entered the Australian Antarctic Economic Exclusion Zone four days ago, but had not expected to encounter the Japanese fleet for another month.

He said the earliest his crew had found the Japanese fleet on previous expeditions was Christmas Day, 2005. "Usually it's not until the end of January that we find them, so we're quite happy that we found them this early," he said.

"I think this will have a significant impact on their quota and on their profits." He remained scathing of the federal government's call for calm in the situation. A joint statement from Foreign Minister Stephen Smith and Environment Minister Peter Garret was made on the matter earlier this month.

"We call upon all parties to exercise restraint and to ensure that safety at sea is the highest priority," the statement read. Capt Watson said the government was playing "silly games".

"We have Australian citizens on board here who are quite ready to inform the Japanese that they are in contempt of an Australian Federal Court order, and this is really something the government should be doing instead of playing silly little games in Tokyo, which isn't going to get anywhere," he said. "I think he (Stephen Smith) should condemn the fact that whales are being killed here illegally." "All of this talk about diplomacy isn't saving any whales."

Capt Watson expects to remain at sea until March. AAP