CANBERRA, April 2 -- Political will in Australia and Japan will be necessary to uphold the International Court of Justice (ICJ) ruling against Japan's "scientific" whaling program in the Southern Ocean, a leading Australian international law expert said Wednesday.

Ensuring Japan complied with the ruling depended on two monitoring mechanisms, Australian National University Professor of International Law Don Rothwell told Xinhua in a phone interview.

"One is the scientific committee of the International Whaling Commission that does have oversight of all proposed research programs that are conducted by member states. Literally the only other way that that compliance can be monitored is through additional legal action by states," said Rothwell.

However, none of the scientific committee's recommendations or resolutions were binding on International Whaling Commission members, "so it's a bit of a toothless tiger," he said.

"It can raise its objections, it can raise its concerns, but states are not bound by any of those objections or concerns because the committee doesn't have the ability to pass any form of binding resolution or sanction against members," said Rothwell.

"I think Japan has pretty much been put on notice as to how any future program that it might seek to construct would be subject to monitoring and oversight by the international community more generally."

Prior to Monday's ruling, members were "operating in a vacuum" as to how Article 8 of the international Whaling Convention, which enabled scientific whaling, could be interpreted.

"Japan's position was, as argued before the court, that Article 8 was, to use their terms, 'a self-judging provision.' In other words, Japan could unilaterally interpret Article 8 in that no other member of the International Whaling Commission or even an international court could seek to exercise any judgment as to its legal validity or not," he said.

"The judgment of the international court has clearly quashed that argument fairly and squarely."

Although Japanese officials had suggested they would abide by the ruling, they could still possibly withdraw from the International Whaling Commission, which would open up other legal avenues, he said, without specifying them.

"The outcome of a case like this significantly advances the ability of other states to diplomatically use this as a lever in terms of placing pressure on states that are not seen to be acting in compliance with Article 8," said Rothwell.

However, any resumption of whaling would test the resolve of Australian Prime Minister Tony Abbott's government, which was elected in September last year.

"One would have to recognize that the Abbott government might take a different view on these matters compared to more recent Australian governments who have been quite proactive in terms of legally challenging Japan's position with respect to whaling."