Australia yesterday warned Japan that "diplomacy comes to an end this year" on whaling, after presenting a bold plan to phase out the controversial hunts in the Southern Ocean.
Prime Minister Kevin Rudd, repeating his threat to sue Japan, said time was running out on its practice of killing hundreds of minke whales near Antarctica each year in the name of scientific research.
"We are saying loud and clear to our friends in Japan that Australia does not support the continuation of commercial or scientific whaling in the Southern Ocean, we have a very basic position," Mr Rudd told reporters.
"What we further said in recent times, and that has been the source of some diplomatic difficulty between us, is that if Japan cannot come forward with a proposal which reduces its current catch to zero over a reasonable period of time, then we have no alternative but to initiate appropriate legal action."
The demands, made in an Australian proposal to the International Whaling Commission (IWC) this week, were described as "extremely regrettable" by Tokyo, which stood by the legality of its whaling activities.
Mr Rudd said Australia's position on the issue had shifted in recent weeks, and insisted he was serious about taking Japan to the International Court of Justice (ICJ).
"What I have said before is that we would try diplomacy," Mr Rudd said. "I've signalled very clearly in the last week or two that diplomacy comes to an end this year.
"Absent an agreement along the lines I described before, international legal action will commence this year."
Under the Australian plan, released on Thursday, scientific hunting of the giant mammals would end within a "reasonable period" and a five-year timeline set to stop whaling in the Antarctic.
Both Japan and Australia have expressed hope for a diplomatic solution to the impasse, but Canberra has stepped up its rhetoric in recent weeks after high-seas clashes between a Japanese fleet and anti-whaling campaigners.
Tensions flared last week when Mr Rudd bluntly warned Japan before a visit by Foreign Minister Katsuya Okada that it had until November to reduce its whale catch to zero, or face action at the ICJ.
Mr Okada, the first official from Tokyo's new government to visit Australia, described Mr Rudd's ultimatum as "unfortunate", but said his country would fight any court action and seek to prove its activities were legal.