Anti-whaling group Sea Shepherd says it has boxed in the Japanese whaling fleet's factory ship, effectively suspending whaling in the Southern Ocean.
The conservation group located the Japanese fleet on Friday night, and two of its vessels were now ahead and behind the factory ship Nisshin Maru.
Sea Shepherd New Zealand spokesman Michael Lawry said the Japanese fleet, including its harpoon and security vessels, was now leaving the whaling grounds.
"They were heading northeast, out of the area, and the Sea Shepherd vessel Bob Barker was right on the tail of the factory ship, and the Steve Irwin was ahead.''
Mr Lawry said the group's presence had put a stop to Japan's whaling.