At issue is Japan's foray into the Antarctica in November under a program that allows the killing of minke and fin whales for scientific research, despite an international ban on commercial whaling. Opponents say Japan has used the loophole to kill nearly 10,000 whales over the past two decades and sell their meat on the commercial market.
Foreign Minister Stephen Smith said Australia would send a customs ship to pick up the two activists, after the Japanese government asked for help. The activists, from an anti-whaling group, the Sea Shepherd Conservation Society, have been detained on the Japanese harpoon boat Yushin Maru 2 since they leaped aboard uninvited on Tuesday.
The Australian boat would then return the activists to the Steve Irwin, Sea Shepherd's ship.
"The motivation of the Australian government is to secure, as quickly as possible, the transfer so the welfare, the safety and security of the two men concerned is put beyond doubt," Australian Foreign Minister Stephen Smith told reporters in the western city of Perth.
The customs ship belongs to Canberra, a staunch opponent of Japan's whaling program. It was sent to the Antarctic Ocean last month to collect photo and video evidence that might be used in international courts to prove the Japanese program is a front for commercial whaling.
Sea Shepherd founder Paul Watson welcomed Australia's offer, but vowed to defy any requirements that he desist from harassing the whaling fleet. He vowed to resume doing so unless they stopped the killing.
"I"m not going along with any conditions," Watson told the Australian Broadcasting Corp. from the Steve Irwin. "They are down here illegally killing whales, illegally targeting endangered species ... These people are no different than elephant poachers in Africa or tiger poachers in India."
Japan has put its hunt on hold since Benjamin Potts, 28, of Australia, and Giles Lane, 35, of Britain, jumped from a rubber boat onto the Japanese ship's deck after a high-speed chase.
Sea Shepherd says the pair simply wanted to deliver an anti-whaling letter and accused the whalers of taking their members hostage. Japanese whaling officials said the activists were acting like pirates.
Japanese officials said Thursday that repeated attempts to contact Sea Shepherd had failed, and accused them of dragging out the dispute to generate publicity. Sea Shepherd denied that it had been approached by any Japanese officials.
"It has become apparent that it will be impossible to hand the two trespassers back directly to Sea Shepherd," said Hideki Moronuki, a spokesman for the Japanese Fisheries Agency's whaling section, explaining why Australia's help was sought.
The contest over whaling occurs in waters far south of normal shipping lanes, and thousands of miles from the possibility of regular emergency or rescue services.
Australian Prime Minister Kevin Rudd on Thursday urged "restraint on the parties, full cooperation on the part of those involved, to ensure the safe return of these two individuals."