The anti-whaling group Sea Shepherd says its vessel Steve Irwin has spotting the Japanese whaling fleet inside the Ross Sea Dependency and is preparing to intercept the vessels.
The group has accused the Japanese fleet of poaching inside the Southern Ocean Whale Sanctuary in contravention of international law.
It says crew on one of its ships Sam Simon spotted whale guts in the ocean within the protected area, thus confirming poaching, which it claims has been interrupted by the close proximity of the Sea Shepherd fleet.
It says the Japanese fleet including its factory ship, Nishin Maru, its security vessel, and its three harpoon vessels have now fled the area with the Sea Shepherd's three vessels in pursuit.
It says the three harpoon vessels are travelling in formation behind the Nishin Maru, in a bid to block the slipway of the factory vessel, with the Sea Shepherd vessels, Sam Simon, Bob Barker and Steve Irwin closing in.