Two days after Japan's Prime Minister Shinzo Abe arrived in Sydney to further enhance defense ties with Australia anti-whaling group Sea Shepherd released the images.

It can be recalled that commercial whaling was not allowed since 1985 by global moratorium. Only the so-called scientific whaling was allowed. This is the hunting of whales for scientific study. But it was also banned in 2014 by ICJ (International Court of Justice), and so no more whaling was allowed, commercial or scientific.

Japan has reacted, they try to prove that there is enough population of whales and that commercial fishing should again be allowed, and that to carry out scientific research the whale must be killed.

This has drawn criticism from environmental groups, Australian and the UK governments.

Josh Frydenberg, Australia's Environment Minister said killing whales for research is not necessary.

According to BBC, after scientific whaling was banned in 2014, Japan scientific Antarctic whaling was suspended for one season but said they would soon begin another scientific whaling program. And now that Japan has decided to return to Southern Ocean to undertake scientific whaling again, the Australian government is deeply disappointed, Frydenberg said on Monday.

Since any kind of whaling is prohibited by the International Court of Justice and that Japan's whaling has been ruled illegal, the recent violation made by Japan is punishable by either fines or sanctions, said Australian Greens senator Nick McKim.

Spotted in the photos taken by Sea Shepherd on Sunday were the Japanese vessels Nissin Maru, and two smaller boats were seen Yushin Maru and Yushin Maru 2.  Nissin Maru immediately covered the dead whale with tarpaulin when they saw above anti-whaling helicopters while the two smaller boats also covered their harpoons, Eurasia Diary reported.

Wyanda Lublink, captain of Sea Shepherd ship the MY Steve Irwin said "The fact that the Japanese crew went to cover up their harpoons and the dead minke whale on deck just shows that they know what they're doing is wrong."