The International Court of Justice ruled in the landmark case of Australia v Japan, that Japan's JARPA 2 whaling program in the Southern Ocean was not for scientific purposes.

Monday's decision in The Hague ordered that all permits given under the program be revoked.

Japan has said it will abide by the ruling.

Dr Brown said in Launceston yesterday that the court's decision was not only a great day for whales in the Antarctic, but also for Paul Watson.

Mr Watson founded the Sea Shepherd Conservation Society and faces court action in the US for his anti-whaling activism.

Dr Brown praised his fellow environmentalist as ``the hero of this whole outcome''.

He said that while Japan called Mr Watson a ``law-breaker'', the ruling had proven that the Japanese were ``the villains'' through their whaling program in the Southern Ocean.

``The court ruling is a blessing in disguise for Japan, because it's going to protect its reputation from continued harm through those pictures Sea Shepherd brought back of the poor whales being destroyed for no good reason,'' Dr Brown said.

``Their reputation was being tarnished everywhere and they know it.

``I spoke to several ambassadors for Japan when I was leading the Greens in Canberra and it was always a very tense and embarrassing affair.

``Because if you ask me, those ambassadors knew that Japan was doing the wrong thing.''

Dr Brown said that relations between Australia and Japan would improve.

``This thorn in all the meetings between governments has now been removed,'' he said.

``Tokyo will be breathing a sigh of relief that this court ruling lets them off the hook.''

Dr Brown said there was still a great deal more to achieve for the world's oceans, and Sea Shepherd would continue to draw attention to northern hemisphere waters, the ``destruction'' of great fisheries south of Australia, and the killing of sharks in areas including Queensland and West Australian coastal waters.