In a purely symbolic act but one that could inflame bilateral ties, an Australian court has ruled that a Japanese whaling company broke environment laws by killing whales in Australia's Antarctic waters.

The Federal Court of Australia ordered Japanese whaler Kyodo Senpaku Kaisha Ltd stop killing whales in Australia's Antarctic whale sanctuary, saying that unless it was "restrained" it would continue to kill and injure whales. However the court has no jurisdiction outside Australia and the Japanese government denied the whalers were doing anything illegal. "According to the International Whaling Commission, what the Japanese whaling fleet is doing in the South Pacific and Antarctic region is legal," said Tomohiko Taniguchi, a spokesman at Japan's Foreign Ministry. An official at Japan's Fisheries Ministry declined to comment.

An Australian fisheries ship is searching for the Japanese whaling fleet to gather photographic evidence for an international court case aimed at stopping Japan's annual "scientific" hunt. Federal court Judge Jim Allsop ruled the whaler had "killed, injured, taken and interfered with Antarctic minke whales and fin whales and injured, taken and interfered with humpback whales in the Australian Whale Sanctuary in contravention of the Environment Protection and Biodiversity Conservation (EPBC) Act. Allsop also said that while no humpback whales had been killed by the whaling firm, there was evidence that biopsy samples were taken from humpbacks using a crossbow.

While the whalers killed whales outside Australian waters, a significant number of the whales were taken inside the Australian Whale Sanctuary but the judge conceded there was little chance his ruling could be enforced. Unless the respondent's vessels enter Australia, exposing themselves to possible arrest or seizure, the applicant acknowledges that there is no practical mechanism by which orders of the Australian court can be enforced.

Australia's Environment Minister, Peter Garrett, said he would be looking carefully at the judgement to see if it could add weight to an Australian government challenge to whaling in an international tribunal.

Japan has long resisted pressure to stop scientific whaling, insisting whaling is a cherished cultural tradition. Its fleet has killed 7,000 Antarctic minkes over the past 20 years.