A lawyer for Japan's whalers claims the Australian Sea Shepherd ship, Brigitte Bardot, has breached a US court restraining order in the Southern Ocean.
In the first test of the conservation group's shift of its anti-whaling campaign to Australian hands, the lawyer claims the Bardot closed on the harpoon ship, Yushin Maru No. 3.
The US Ninth Circuit appeals court imposed an injunction on the Washington State-based Sea Shepherd Conservation Society (SSCS), restraining its ships from attacking the whaling fleet, or approaching within 500 yards (457 metres).
A lawyer for the Institute of Cetacean Research in Seattle, John Neupert, said the group's fast reconnaissance boat approached from behind Yushin Maru No. 3 and came within 20.25 yards (18.5 metres) of the harpoon ship on January 29.
"This is a clear violation of the injunction," Mr Neupert said in his letter to SSCS lawyer Charles Moure.
Mr Neupert called for written acknowledgement from SSCS and the Bardot's skipper, Jean Yves Terlain, that they would comply with the injunction, or the ICR would pursue a contempt action.
But the group's Melbourne lawyer, John McMullan, has written back, saying Sea Shepherd Australia Limited is responsible for the Antarctic campaign.
Mr McMullan said the American SSCS had no shareholding in, or control of SSAL, which is run by Australians Bob Brown, the former Greens leader, and Jeff Hansen.
"SSAL, in respect of its actions in the Southern Ocean, is not subject to the order of the USA courts," Mr McMullan said.
"Further, SSAL says that ICR is in breach of Australian law," Mr McMullan said.
He said the ICR was breaching an Australian Federal Court injunction against whaling in the Australian Exclusive Economic Zone, granted in the 2008 Humane Society International case.
Meanwhile, the International Fund for Animal Welfare has released a report showing that over the past 25 years, direct whaling subsidies cost Japanese taxpayers almost 30 billion yen ($A310 million).
Most recently the Institute of Cetacean Research's whaling fleet management company, Kyodo Senpaku, was given permission to apply for a loan of 1.5-2 billion yen ($A15-20 million) to refit the factory ship Nisshin Maru so it could continue operations.
Japan's stockpile of frozen whale meat steadily increased over the past 10 years, to currently stand at nearly 5000 tonnes – or more than four times its size 15 years ago.
"Japan's cruel whaling industry is dying in the water while Japanese taxpayers are being forced to foot the bill," said IFAW's global whales campaign director, Patrick Ramage.
Japan's former whaling commissioner, Masayuki Komatsu, questioned its future.
"And it's not sustainable, right?" he told the ABC. "How long can you, you know, can you get such money from the government?"