But the Japanese ship was photographed yesterday within a few miles of the coast of Macquarie Island, which is part of the state of Tasmania.

The Sea Shepherd anti-whaling group said the harpoon ship continued trailing its vessel, Bob Barker, inside the 12-nautical-mile territorial limit all day.

''Things seem to be reaching a boiling point here,'' the Bob Barker's first mate, Peter Hammarstedt, said. ''It has followed us on circuits of the island, keeping right inside the 12-mile zone.''

The Bob Barker sought refuge at Macquarie Island to try to shake the ship off its stern. As long as some Japanese vessels are able to keep tabs on Sea Shepherd activists, the rest of the fleet can continue whaling.

ANU professor of international law Don Rothwell said if Yushin Maru No.3 was staying close to Macquarie Island it was violating the UN Convention on the Law of the Sea which would normally allow a ship to proceed though these waters.