Japan will robustly defend its whaling programme at the UN's top court this week, Foreign Minister Fumio Kishida said Tuesday, as Sydney and Tokyo ready to do battle over the legality of the hunt.

A day before the oral hearing is due to start at the International Court of Justice in the Hague, Kishida said Tokyo has no intention to back down under pressure.

"Japan will fully engage in the case so the country's position and thinking will be understood," he told reporters.

"Japan's research whaling is a scientific endeavour carried out legally under the International Convention for the Regulation of Whaling, article 8.

"Japan will make this point clearly in the hearing."

While Norway and Iceland have commercial whaling programmes, Japan insists its hunt is purely scientific, although it makes no secret of the fact that the resulting meat ends up on plates back home.

The whaling research is to prove that commercial whaling is viable. The proceeds from sales of the meat partly pay for the programme.

Tokyo defends the practice of eating whale meat as a culinary tradition.

Japan's 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.

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.

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."

Critics question what remains for Japan to conclude about sustainable whale populations after carrying out its research in the decades since the moratorium on international whaling was established.

Japan killed around 6,500 Antarctic minke whales between 1987 and 2005, after the moratorium came into effect, compared to 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.

The haul from Japan's most recent whaling mission in the Southern Ocean was a "record low", the government said earlier this year, blaming "unforgivable sabotage" by activists.

Whalers came back with just 103 Antarctic minke whales, less than half its tally last year, and no fin whales, after repeatedly clashing with militant environmentalist group Sea Shepherd.