September sales of bonded bunker fuel, which are tax exempt as they are sold to ocean-going ships, were up by 8% comapred to August.
The 2.344 million barrels sold reaced a six-month high, according to price reporting agency Platts citing ministry figures.
The increase is attributed to seasonal variation while overall, September's figures were slightly down on year-on-year.
Japan did not import any bonded bunker fuel in September, the report said.
