Japanese government sources have told NHK the United States will allow Japan to temporarily continue importing crude oil from Iran, after the reinstatement of US sanctions.
Washington will reintroduce sanctions against Tehran on Monday.
The US has unilaterally pulled out of the nuclear deal signed between Iran and 6 world powers. It has also been urging other nations to stop importing Iranian oil.
But Secretary of State Mike Pompeo announced on Friday that the US will issue temporary waivers to Japan and 7 other countries, so they can continue oil imports.
Iran accounts for about 5 percent of Japan's oil purchases. Oil wholesalers have halted imports from Iran to prepare for the US sanctions.
The Japanese government intends to notify the wholesalers of the waiver once the US makes it official.
Japanese officials had been requesting since June that the US exempt their country from the import ban.
In September, Foreign Minister Taro Kono told Pompeo the ban would deal a blow to Japanese businesses.