Hardline anti-whaling activists prepared to pursue Japan's Antarctic whaling fleet with the support of a US actress, who criticised Greenpeace for opting out of the annual chase.
The Sea Shepherd Conservation Society, which clashed last year with the eight-ship fleet, bombarding it with stink bombs and briefly boarding a harpoon vessel, departed Australia on Wednesday for the Southern Ocean.
Ms Hannah, who starred in the 1980s films Blade Runner and Splash, travels part-way on Sea Shepherd flagship Steve Irwin.
Sea Shepherd will be alone during this year's five-month hunt, in which the Japanese aim to cull close to 1,000 endangered fin and minke whales under an international loophole allowing scientific whaling for research.
Environmental watchdog Greenpeace has previously sent a ship in pursuit of the fleet, but has been a vocal critic of the tactics favoured by Sea Shepherd founder Paul Watson.
In past years, Watson's ship has collided with the whalers in self-styled "pirate" protest actions.
"If Greenpeace would join forces with Sea Shepherd they would shutdown the whaling industry right away.
"If they were really serious and held their convictions they could accomplish this," Ms Hannah told Australian Associated Press.
Greenpeace said it welcomed Ms Hannah's support for an end to whaling, but would concentrate efforts on swaying public opinion in Japan, where whaling is regarded as a cherished tradition.
"We'd like her to know that ... we think the best place to win this campaign in is Japan," Greenpeace Whales Campaigner Reece Turner said.
Australia's government last month said it would not monitor the Japanese fleet this year with a fisheries patrol ship after protests from Tokyo last year. Environment Minister Peter Garrett denied diplomacy had blunted his opposition to the cull.
"What Mr Garrett has done is say to Japan, you continue the slaughter, just stay out of Australian (Antarctic) waters," conservative opposition politician Greg Hunt said.
Tokyo is still Australia's largest export market worth €12 billion in 2007-08, although China edged ahead as Canberra's main two-way partner with trade worth €32 billion.
As well, Japan and Australia are part of a three-way security pact counting the US, making Canberra reluctant to carry through with a threat of international legal action to stop the Japanese hunt, which Mr Garrett last year called "barbaric."
"We are extremely disappointed with the weak approach this government is taking on whaling," Australian Greens Senator Rachel Siewert said.