Australia is considering taking a high-stakes legal gamble by dragging Japan back to the international court in an attempt to halt the killing of whales.
The Turnbull government is also examining plans to send surveillance aircraft to monitor the Japanese whaling fleet, which set sail last week with plans to hunt up to 330 whales in the Southern Ocean.
Sea Shepherd activists departed Melbourne on Monday with hopes of confronting the Japanese vessels and disrupting the hunt. 
The prospect of a high-seas clash over the summer whale hunt will pose an awkward challenge for the government which is considering Japan's bid in Australia's largest-ever defence acquisition, the multi-billion dollar Future Submarine project.
Fairfax Media understands the government is exploring legal options to stop the whale killings, despite Japan's shock decision to withdraw from jurisdiction of the International Court of Justice in disputes over "living resources of the sea".
The court last year ruled Japan's so-called "scientific" whaling program illegal after Australia brought a case to challenge the reasons for the hunt.
But Tokyo has since sought to circumvent the ruling by drawing up a new rationale for whaling, known as NEWREP-A, arguing this will conform with legal obligations under a long-standing international moratorium on commercial whaling.
Japan has also made a special declaration to United Nations Secretary-General Ban Ki-moon to exempt itself from the court's jurisdiction in a bid to prevent any challenge.
Australia criticised Japan's "unilateral" action after the new whaling rationale was made public last month, but the government is yet to make a final decision on further court action.
Commonwealth lawyers are understood to have given little hope a fresh case will succeed, given Japan's withdrawal decision.
But there is a view in government an honourable loss that still puts Japan in the international spotlight would be an acceptable outcome, and help contain damage to the diplomatic relationship.
Japan is planning to kill 4000 whales over 12 years, arguing this is necessary for research, but has also declared the "lethal sample size" could be changed at anytime.
Foreign Affairs Minister Julie Bishop raised Australia's disappointment over the resumption of whaling with her Japanese counterpart Fumio Kishida last month in Sydney.
France has taken a stand against the Japanese hunt, with French ambassador to Australia Christophe Lecourtier telling reporters in Hobart that France was "very close" to the Australian position.
British high commissioner Menna Rawlings said last week Britain was disappointed with Japan's decision and was talking to Australia about possible next steps.
There is surprise in government ranks that Japan's decision to resume the whale hunt has not sparked wider public outcry in Australia. - but also an expectation that attention will sharpen in coming weeks when the killing commences, especially if Sea Shepherd clashes with the whalers.
Japan's decision to go whaling again has been widely reported globally, including warnings Japan may come to regret declaring itself unbound by international agreements as a precedent in territorial disputes with China and South Korea.
The South China Morning Post published an editorial on Monday calling for Japan to reverse course, warning "Japan's international standing is being put at risk by the latest hunt".
Adding to judicial pressure for action by the government, the Federal Court on Friday published the full decision in a case against the Japanese whalers, describing their actions as "a wilful and voluntary" contempt of the court. Justice Jayne Jagot fined the whaling company, Kyodo Senpaku Kaisha, $1 million for contempt of an injunction against the killing of minke whales in the Australian Antarctic Whale Sanctuary
theage.com.au - Read more