A row over whaling threatened to overshadow a visit to Australia by Japan's foreign minister on Saturday, a day after Prime Minister Kevin Rudd warned of legal action to stop Japan's annual whale hunt. Australia opposes the slaughter and Rudd on Friday said it would take Tokyo to the International Court of Justice over the issue before the start of the next whaling season in November, unless Japan stopped the practice. 'Specifically, what we're putting to the Japanese is to take where they are now, which is the slaughter of some hundreds of whales each year, and reduce that to zero,' Rudd said Friday. 'If we don't get that as a diplomatic agreement, let me tell you, we'll be going to the International Court of Justice.' Foreign Minister Katsuya Okada's two-day visit to Sydney and Perth, the first by an official of Japan's five-month-old government, coincided with an anti-whaling protest outside the Japanese embassy in Canberra. About 30 people demonstrated outside the gates of the mission, calling for an end to the annual hunts in the Southern Ocean, Australian news agency AAP said. 'We would like to remind Minister Okada that no matter what the outcome of the talks with the government are, if he intends to continue this barbaric slaughter Sea Shepherd will always be there,' Benjamin Baldwin, a spokesman for the radical activist group said. Militant activists onboard Sea Shepherd vessels are pursuing the whaling fleet in the Southern Ocean, attempting to hinder their slaughter of whales by throwing stink bombs onto their decks and getting in the way of their boats. This season's clashes have been particularly fierce, with one encounter leaving the activists' high-speed powerboat Ady Gil sliced in two and sinking. Ady Gil captain Pete Bethune later stole aboard one of the Japanese ships, intending to make a citizen's arrest of its skipper and hand over a three million US dollar damage bill. He remains in custody on board. Okada, who will also discuss defence, nuclear disarmament and climate change during his meetings with Rudd, Defence Minister John Faulkner and Foreign Minister Stephen Smith, visited a Japanese school in Sydney after his arrival. He was due to meet Rudd at his Sydney residence Saturday before travelling to Perth to meet with Smith on Sunday. Australia, along with New Zealand, has consistently opposed Japan's killing of hundreds of whales each year via a loophole in an international moratorium that allows 'lethal research'. Japan's new government has maintained its support for whaling, which has deep cultural significance for the Japanese people, since coming to power in September. Before coming to Australia, Okada said Japan's research whaling was a legal practice carried out in public waters under the international convention. 