The country's withdrawal, which will be officially announced to the country as early as next week, is planned for 2019 after years of debate between pro- and anti-whaling members of the IWC.
Japan's request for a resumption of commercial whaling was most recently denied at the IWC meeting in September.
At September's IWC meeting in Florianópolis, Brazil, anti-whaling nations led by Australia, the European Union and the U.S. voted down a Japanese proposal to change the decision-making process - a move that would have made it easier for Japan to secure enough votes to end the commercial whaling ban.
While Japan halted commercial whaling in line with a moratorium adopted in 1982 by the IWC, it has hunted whales since 1987 for what it calls "scientific research" purposes. A hunt in the Antarctic was, however, even after withdrawal from the IWC is unlikely, the unconfirmed report.
Japanese officials have said the whaling organization is supposed to pursue sustainability but has become an anti-whaling body. That effort failed in September when it lost a vote among the organization's 89 member countries.
Japan to withdraw from International Whaling Commission to resume hunts
Japan needs to notify the IWC by January 1 if it wished to leave. Japan had been threatened previously, and, if necessary, from the IWC to withdraw. Not satisfied with harpooning whales, it now looks like Japan is threatening to harpoon the future of the IWC.
Darren Kindleysides, chief executive of the Australian Marine Conservation Society, said: "Leaving the IWC would set a very unsafe precedent for other global treaties and conventions". Critics accuse Japan, however, has always been to use science as a cover for commercial whaling by the back door.
Iceland, along with Norway, openly defies the IWC's 1986 ban on commercial whale hunting.
Japan's whaling practices remain a deep point of contention in the otherwise strong relationship between Australia and Japan.
Darren Kindleysides, CEO of the Australian Marine Conservation Society, said Japan would have "turned its back on the worldwide community" should it follow through with its plans to withdraw.
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