Updated

A support vessel for the Japanese whaling fleet is sailing in Australian waters in pursuit of anti-whaling activists, Australia said after protesting to the Tokyo government.

Environment Minister Tony Burke said his government received confirmation Thursday that the Shonan Maru No. 2 had entered Australia's exclusive economic zone near Macquarie Island in the Antarctic Ocean. The Australian embassy in Tokyo protested to the Japanese government, he said.

"Australia has made it clear to Japan on a number of occasions that vessels associated with its whaling program are not welcome" in Australia's territorial waters or economic zone, he said.

The Shonan Maru No. 2 is owned by the Japanese government and provides security for the whaling fleet conducting the country's annual hunt.

The ship tailed anti-whaling ship Bob Barker over two days toward Macquarie Island, said Bob Brown, mission leader of the Washington state-based Sea Shepherd Conservation Society.

Brown said the Shonan Maru No. 2 stopped just outside Australian territorial waters but remained inside Australia's exclusive economic zone Friday as the Bob Barker proceeded up the island's coast. Australia's territorial waters extend 12 nautical miles (22 kilometers) from the island, but it claims exclusive economic rights within 200 nautical miles (370 kilometers).

"Tokyo has ignored the call from the federal government for this part of the whaling fleet not to enter our Exclusive Economic Zone," Brown, a former senator, told Australian Broadcasting Corp. radio.

Glenn Inwood, spokesman for Japan's Tokyo-based whaling organization, said there was no legal obstacle to Japanese ships entering either area.

He said Japan was forced to defy Australia's wishes because Sea Shepherd deploys dangerous tactics to sabotage the whaling fleet.

"Since Sea Shepherd has been putting Japanese lives and property at risk, it's been necessary to move as close to Australian territorial waters as possible to keep an eye on them," Inwood said.

A year ago, three anti-whaling activists boarded the Shonan Maru No. 2 and were held there for several days before being transferred to an Australian customs ship. No charges were brought. In 2010, the ship and a Sea Shepherd speed boat collided and the speed boat sank, but no one was injured.

Australia maintains the hunts violate Japan's international obligations and is seeking a ruling by the International Court of Justice in the Hague.

Japan says it hunts whales for scientific purposes, an allowed exception to the international whaling ban, though activists say the hunts are a cover for commercial whaling because whale meat not used for study is sold for consumption in Japan.

Japan decries Sea Shepherd as a terrorist group that risks lives through tactics used to obstruct the whaling fleet.