The federal government has condemned Japan after one of its ships was caught whaling in the waters off Antarctica.
Anti-whaling group Sea Shepherd has released photos showing a dead minke whale on the deck of the Nisshin Maru ship in the Australian whaling sanctuary.
It follows Japanese Prime Minister Shinzo Abe's weekend meeting with Malcolm Turnbull in Sydney.
Environment Minister Josh Frydenberg said the government was "deeply disappointed" that Japan had decided to return to the Southern Ocean.
"Australia is opposed to all forms of commercial and so-called 'scientific' whaling," he said in a statement on Monday.
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"It is not necessary to kill whales in order to study them."
He said Australia would continue its efforts in the International Whaling Commission to strongly oppose whaling and promote whale conservation.
"No country has done more to try to end whaling than Australia."
Labor's environment spokesman Tony Burke also condemned the act and Japan's continuing defiance of a 2014 international court ruling that deemed it illegal.
"We need to respond when we see the law broken, and a ruling by the International Court of Justice flouted," he said.
The opposition has called on the prime minister to pursue all available legal avenues to end illegal whaling in the Southern Ocean.
