Australia will take its fight to stop Japan hunting whales in the Antarctic to the UN's top court on Wednesday, in what activists say is a make or break case for the giant marine mammals' future.
Canberra will argue before the International Court of Justice that Japan is exploiting a loophole by continuing to hunt whales as scientific research in spite of a 1986 International Whaling Commission (IWC) ban on commercial whaling.
Australia wants ICJ judges to order Tokyo to stop its JARPA II research programme and "revoke any authorisations, permits or licences" to hunt whales in the Southern Ocean.
While Norway and Iceland have commercial whaling programmes, Japan insists its programme is purely scientific, although making no secret that the resulting meat ends up on plates back home.
The whaling research is to prove that commercial whaling is viable, and the proceeds from sales of the meat partly pay for the programme.
In its application, Australia accuses Japan of breaching its obligation "to observe in good faith the zero catch limit in relation to the killing of whales."
Japan killed around 6,500 Antarctic minke whales between 1987 and 2005, after the moratorium came into effect, compared with only 840 whales for research purposes in the 31 years prior to the moratorium, court papers said.
A further 2,500 minke whales were killed between 2005 and 2009 under the JARPA II programme.
Minke whales are not endangered, but JARPA II also allows for the killing of endangered mammals including humpback and fin whales.
Australia said in its court filing that Japan had not killed any humpback whales, but that at least 13 endangered fin whales were killed during the programme's 2005-2007 feasibility stage.
"We will now have our day in court to establish once and for all that Japan's whaling hunt is not for scientific purposes and is against international law," Attorney-General Markus Dreyfus, who is to front Canberra's case, said when court dates were announced in April.
The Asian nation's annual whale hunt has long drawn criticism but Tokyo defends the practice, saying that eating whale meat is a culinary tradition.
Japan, whose lawyers will begin to address the top UN court on July 2, has set up a special taskforce at its foreign ministry.
A taskforce official told AFP that Tokyo will defend its whaling programme as legitimate under the International Convention for the Regulation of Whaling (ICRW).
"Japan's research is a scientific study and legitimate under the convention. We will stress that point in the oral hearings," said the official, who declined to be named.
A defiant Fisheries Minister Yoshimasa Hayashi vowed in February that Japan would never stop hunting whales, saying it was a "long tradition and culture" in his country.
Japan announced in April that this year's whaling haul from the Southern Ocean was at a "record low" because of "unforgivable sabotage" by activists.
The hunt caught 103 Antarctic minke whales, the lowest haul since "research whaling" began in 1987, thanks to high-seas disruption by militant anti-whaling group Sea Shepherd.
Sea Shepherd in March filed a suit in a Dutch court against the crew of a Japanese whaling ship, alleging piracy and attempted manslaughter after they clashed in the Antarctic Ocean.
Japan's Institute for Cetacean Research has in turn accused Sea Shepherd boats of harassing and even ramming its whaling ships.
Geert Vons, Sea Shepherd's director in the Netherlands where two of its ships are registered, said that the ICJ suit was a make or break case.
"If nothing happens now, nothing else is going to happen," he told AFP.
"If Australia wins the case, this will be a huge lift for our cause."
A ruling in the hearing, in which New Zealand will also make a submission, is not expected for several months.
Established in 1945, the ICJ is the UN's highest judicial organ and it settles disputes between states. It is the only one of six principal UN organs not located in New York.