TOKYO - Australia, one of most vocal opponents of Japanese whaling hunts in the Antarctic, threatened Monday to take legal action against the lethal expeditions, about a week after Tokyo began its latest hunt.

Australia's foreign and environmental ministers said in a statement that the country had joined 32 others to oppose the Japanese expedition that left last Tuesday to catch up to 333 minke whales in the Antarctic.

The International Whaling Commission banned commercial whaling in 1986, but Japan has continued killing whales under an exemption for research.

"There is no scientific basis to include lethal methods in Japan's whaling program," Australian Foreign Minister Julie Bishop and Environment Minister Greg Hunt said in a statement issued in Canberra, Australia's capital. They said information needed for the management and conservation of whales should not involve lethal methods.

"We are also exploring options for further legal action," the statement said.

Australia filed a lawsuit with the International Court of Justice in 2010 over Japanese whaling in the Antarctic. The ICJ responded to the lawsuit, which New Zealand later joined, by ruling last year that the hunts were not scientific, forcing Tokyo to revise its Antarctic whaling program.

Australia also said last week that it might send a boat to shadow the current Japanese fleet.

Joji Morishita, Japan's commissioner to the International Whaling Commission, told reporters in Tokyo on Monday that Japan had met the ICJ's new requirements. He said that Japan only wants to make whaling sustainable and promote healthy whale populations.

Japan's whale catch has fallen in recent years in part because of declining domestic demand for whale meat. Protests by the anti-whaling group Sea Shepherd have also contributed to the decline. Japan's government has spent large amounts of tax money to sustain the whaling operations.