But 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.

Japan plans to hunt almost 1,000 minke and fin whales for research over the Antarctic summer, but has abandoned the cull of 50 humpback whales after international condemnation and a formal diplomatic protest by 31 nations.

Humane Society International (HSI) launched legal action against Kyodo Senpaku Kaisha Ltd in 2004, seeking a federal court injunction against harvesting in the Australian Whale Sanctuary.

The hearing was derailed in 2005 when the Australian government intervened on the grounds it could spark a diplomatic row with Japan, arguing the matter of whaling was best left to governments. The full bench of the federal court ordered the proceedings resume in 2006.

Federal court Judge Jim Allsop ruled on Tuesday 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."

CROSSBOW

Allsop 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.

"I am satisfied that this non-lethal method of sampling amounted to injuring, interfering with and treating a cetacean within the definition of the EPBC Act," he said.

While the whalers also killed whales outside Australian waters, a "significant number of the whales were taken inside the Australian Whale Sanctuary", Allsop said.

But the judge conceded there was little chance his ruling could be enforced.

"Unless the respondent's vessels enter Australia, thus exposing themselves to possible arrest or seizure, the applicant acknowledges that there is no practical mechanism by which orders of this court can be enforced," he said.

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.

"The Commonwealth wasn't a party to this case but our intention to continue to have an overall, holistic and fair-dinkum approach to opposing Japanese so-called scientific whaling is absolutely clear," Garrett told reporters.

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.