The decision, which will be officially announced as early as next week, comes after decades of confrontation between pro- and anti-whaling members of the IWC.
The country is withdrawing from IWC and, with that, it is expected to resume commercial whaling activities.
"Japan's official position, that we want to resume commercial whaling as soon as possible, has not changed", the official said, quoted by the Guardian.
Japanese media are reporting Tokyo has made a decision to withdraw from the International Whaling Commission ((IWC)) to resume commercial whaling - just three months after anti-whaling nations, including Australia, voted down a Japanese push to end the ban. Whale meat now sold in Japan is obtained as a "by-product" of whaling research in the Antarctic Ocean and the Northwest Pacific, except for imports from Iceland and elsewhere.
If Japan notifies the United States - which is entrusted with managing the IWC's withdrawal and joining process - by the end of this year of its wish to withdraw, Japan would pull out on June 30 next year.
Japanese officials claim that populations of certain types of whale - such as the minke - have recovered sufficiently to allow the resumption of "sustainable" hunting.More news: Trump Calls Michael Cohen a 'rat'
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Australia's environment minister, Melissa Price, said it remained opposed to "all forms of commercial and so-called "scientific whaling", adding: "While we would strongly prefer Japan to remain a party to the convention and a member of the commission, the decision to withdraw is a matter for Japan".
Rothwell, who is one of Australia's leading global law experts, said the significance of a Japanese departure from the IWC can not be underplayed, given Japan's previous strong commitment to multilateral institutions and worldwide law.
According to Kyodo, Tokyo is now planning, next year, from the Commission to withdraw the commercial hunting of marine mammals.
1994 - Japan launches research whaling in the Northwest Pacific. Supposedly they wanted to waters, however, only in the own coast, as well as in Japan's economic zone, to go on whaling. Japan suspended catching whales for commercial purposes in 1988.
Except for Japan, Norway and Iceland catch whales - both Nations fish in the North Atlantic and do not see the IWC rules-bound.
But the IWC has continued to invoke the moratorium.