GREENPEACE HAS accused Japan of making a mockery of international law after reflagging a deregistered ship, which has rejoined the hunt for whales in Antarctica.
The refuelling tanker, known as the Oriental Bird, was decommissioned in October 2008 after it was fined $US10,000 (AU$15,000) by the Panama authorities for breaching international environmental laws.
The environmental group said Japan has sent the ship back into operation with the whaling fleet in Antarctic waters and renamed it Hiyo Maru.
Japan has ratified the treaty - International Conservation and Management Measures by Fishing Vessels on the High Seas - which bans the practice of reflagging to circumvent the law.
The Japanese Fisheries Agency told the Australian Broadcasting Corporation there is a refuelling ship with the fleet, but it will not confirm if it is the Hiyo Maru.
- Sarah Sharples