Australia argued that Japan's whaling program is untenable and dangerous in its opening address to the International Court of Justice in the Hague.

The Government launched the legal action in 2010 and now it has come down to submissions by both sides over three weeks.

When the court hands down its decision later this year, there will be no appeal, so the stakes are high for all parties.

Bill Campbell QC, who has advised the Government on international law for more than 30 years, told the court Japan erroneously asserts the program for scientific research.

"Japan seeks to cloak its commercial whaling under the labcoat of science. It simply isn't science," he said.

"What Japan is doing in the Southern Ocean is patently for commercial purposes.

"The amount of catch they're taking, which in the case of minke whales, they can take up to 935 minke whales a year.

"They also sell the product into various places in Japan."

Mr Campbell told the 16 presiding judges that the court has a genuine opportunity to decide what does and does not constitute scientific activity.

He told the court that if each of the 89 countries signed up to whaling regulations made the same decisions as Japan, the consequences would be disastrous.

Australia says more than 10,000 whales have been killed since 1988 as a result of Japan's programs.

It alleges that puts the Asian nation in breach of international conventions and its obligation to preserve marine mammals and their environment.

Australia's address will last for three days, while Japan makes its first submission next week

Japan defends 'sustainable' practice

Sorry, this video has expired Mary Gearin reports on the start of the challenge

Japan says the research is conducted to "better understand the sustainability of whale stocks" and it does not exclude a push for commercial whale hunting to be authorised in the future.

It says that the number of minke whales it hunts is much less than their birth rate and is therefore sustainable.

Nori Shikata, spokesman for the Japanese government on the case, says Japan will rely on the provision for scientific whaling in its case.

"We are abiding by the specific provision under the convention... which allows contracting governments to engage in research whaling for scientific purpose," Mr Shikata said.

"Japan is conducting both non-lethal and lethal research program. Some of the data cannot be obtained by non-lethal means."

Japan's deputy foreign minister Koji Tsuruoka says "Australia's claim is invalid".

"Japan's research whaling has been conducted for scientific research in accordance with international law," he told the court.

"[Japan is] proud of its tradition of living in harmony with nature, and utilising living resources while respecting their sustainability."

Hearings are set to last until July 16. New Zealand is supporting Australia's case and will also be making a submission.

A ruling is not expected for several months.

Established in 1945, the International Court of Justice is the United Nations' highest judicial body and settles disputes between nation states.

It is the only one of five principal UN bodies not located in New York.

ABC/AFP