Sea Shepherd activists say they expect aggressive tactics from Japanese whalers as they begin their 10th annual campaign in the Antarctic.
Anti-whaling group Sea Shepherd says it expects aggressive tactics from Japanese whalers as it begins its 10th annual campaign to protect the giant mammals.
Sea Shepherd boat The Bob Barker is expected to leave Hobart on Wednesday morning to join its fleet as part of Operation Relentless, in an effort to stop the culling of 1132 whales in the Antarctic.
Sea Shepherd spokesman Adam Burling said he was expecting the whalers to attempt to flood the engines of the vessel.
"The Japanese have been increasing their aggressiveness these past few years," Mr Burling told AAP.
"They did a million and half (dollars) in damage to the Bob Barker last year."
Japanese whalers and Sea Shepherd activists have routinely clashed violently in exchanges that have seen stink bombs thrown at Japanese crew and water jets trained on protesters.
The fleet of three ships - which include The Steve Irwin and The Sam Simon - will deploy smaller "zodiac" vessels to try and obstruct the whalers.
Two Japanese whaling ships and a surveillance vessel left the port of Shimonoseki on December 7 for the annual hunt in the Antarctic Sea.
Japan says whales are studied as part of a bid by its whaling research institute to prove their populations can sustain commercial whaling.
Activists charge Tokyo's "research whaling" is a cover for commercial whaling, banned under an international agreement.
Japan's whaling catch fell to a record low of 103 Antarctic minke whales last season, a drop attributed to the anti-whaling group.
The Bob Barker and its 100 crew may try to intercept the Japanese vessels before they reach the Antarctic area where the whaling is to occur.
Comment has been sought from Japan's Institute of Cetacean Research (ICR).
In February, the pro-whaling group accused Sea Shepherd activists of attempting to sabotage two whaling ships - which the ICR calls research ships - by deploying wire entwined ropes to entangle the rudder of one ship.
On December 10, Environment Minister Greg Hunt said he was about 10 days away from announcing how Australia would monitor Japan's whale hunt.
Mr Hunt pledged repeatedly in the lead-up to the September election that a coalition government would send a Customs vessel to Antarctica to monitor the hunt.