Humane Society International (HSI) said in a statement that, if the reports were confirmed, they would mark a welcome end to whaling in the Southern Ocean.
Japan will inform the IWC of its decision by the end of the year, according to Kyodo news agency.
The moratorium on commercial whaling has been in force since 1986.
At September's IWC meeting in Florianópolis, Brazil, anti-whaling nations led by Australia, the European Union and the USA 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.
Japanese want to be able to hunt whales again. In contrast, the IUCN lists the Antarctic minke whale (B. bonaerensis) as "near threatened".
The nation's attempts over the last 30 years to resume commercial whaling of relatively abundant species such as minke whales have always been stymied by countries such as Australia and New Zealand. Iceland even left the IWC before returning with the stipulation that it could object to the ban and continue its hunt.
Kyodo quoted unnamed government sources as saying Japan would abandon its controversial, and expensive, expeditions to the Southern Ocean and instead permit whaling fleets to operate in its coastal waters and exclusive economic zone (EEZ).
Japan has since switched to what it calls research whaling, and says stocks have recovered enough that commercial hunts should resume.
In September it proposed the ban should be lifted, claiming whale numbers are increasing, but anti-whaling nations led by Australia, the European Union and the United States voted down Japan's proposal.
She also fears that Japan may recruit other pro-whaling nations to leave the IWC, "leading to a new chapter of widespread and unauthorised killing of whales for profit".
Japan joined the organisation in 1951. Japan's Antarctic catch is now capped at 333 whales a year - about a third of the quota before a 2014 International Court of Justice ruling found that Japanese research whaling wasn't sufficiently scientific.
Japan cut back on its catch after a 2014 worldwide court ruling. "If Japan is serious about the future of the world's whales, they would not leave the IWC".