Anti-whaling group Sea Shepherd has accused the Australian government of reneging on a promise to monitor Japanese whaling, after capturing graphic images of the latest slaughter in the Southern Ocean.
Former Greens leader and Sea Shepherd Australia chairman Bob Brown said the Abbott government had failed to deliver on its promise to send an aircraft to the Southern Ocean to monitor the annual whaling season.
Dr Brown went further, using the graphic footage of the carcass and blood-strewn deck of the Japanese vessel Nisshin Maru to urge Australia and New Zealand to send naval vessels to uphold the region's international whale sanctuary.
"This bloody operation would simply not be occurring if we had prime ministers in Canberra and Wellington with the spine to stand up to this illegal operation," he said in Hobart.
"There should be naval vessels down there to defend Australia's sovereignty and its whales in our backyard.
"A Customs vessel was promised, with surveillance. That hasn't happened. As a minimum (they should) keep that election promise."
Federal Environment Minister Greg Hunt insisted the government was "committed" to what would be only the second-ever whaling monitoring mission.
"It will be the first such mission in six years," he said. "It will also allow us to monitor multiple ships in a diversely spread fleet. It is curious that both the Greens and the ALP were silent over the last six years. "
Mr Hunt before Christmas said the government would send an aircraft to monitor the Japanese whaling, after promising during the election that Australia would send a ship to the Southern Ocean.
Senior federal Labor MP Anthony Albanese said the Australian people were entitled to ask why the Abbott government had reneged on its commitment to send its own vessel to monitor Japan's hunt.
"I think people are entitled to say 'why did they say one thing before the election and another after the election?''' Mr Albanese told reporters in Sydney.
"They made very clear commitments.
"And putting an aerial surveillance flight over (the area) will not achieve anything.''
Sea Shepherd says it is now pursuing the Japanese fleet after finding all five of its vessels in the Southern Ocean.
The Sea Shepherd fleet, comprising the Steve Irwin, the Bob Barker and the Sam Simon, says it plans to disrupt or shut down their whale-killing operations.
The Steve Irwin's helicopter first spotted the Nisshin Maru, in New Zealand's sovereign waters in the Ross Dependency Antarctic region and inside the internationally recognised Southern Ocean Whale Sanctuary.
The Sea Shepherd group says its footage of three dead protected minke whales on the deck of the Nisshin Maru was shot when the factory ship was first found.
A fourth whale, also believed to be a minke, was being butchered on the deck.
The Sea Shepherd group says its fleet will do what it can to ensure no more whales suffer at the hands of the Japanese.
"Sea Shepherd will remain relentless in driving these fake, desperate and subverting 'scientists' back to Tokyo," the Steve Irwin's captain, Sid Chakravarty, said.
Japan insists its annual whale harvest - which Dr Brown said would this year destroy 935 minke whales, as well as humpback and fin whales - is a scientific operation.
Last June, the New Zealand government joined the Australian government's challenge to the legality of Japan's whale hunt in the Southern Ocean Whale Sanctuary at the International Court of Justice.
A judgment in the case is yet to be delivered.