The Reuters report said that South Korea's oil imports from Iran rose 102.4 percent in February from a year earlier, while its total crude imports rose by 20.8 percent year on year to 96.7 million barrels last month.
The report cited data from the state-run Korea National Oil Corp (KNOC).
This is while an earlier report, again by Reuters, had put the figure at just over 90 percent.
It said Seoul bought 1,064,337 tons of Iranian oil last month, or 269,020 barrels per day (bpd), almost two times higher than the 557,174 tons a year earlier.
That report, citing Korean customs data, said in the first two months of 2016, the world's fifth largest oil importer brought in 1,923,560 tons, or 486,196 bpd, of crude from Iran, versus 830,800 tons in the same period in 2015.
Energy hungry South Korea plans to boost imports of Iranian oil, especially condensate, this year to meet growing demand.
The Asian country imported a total of 12.92 million tons of crude last month, or 3.26 million bpd. The total was 20 percent higher than the 10.74 million tons imported in February of 2015.
Iran now reportedly produces around 3.1 million bpd of oil as it seeks to regain market share after sanctions were effectively lifted in January.
The sanctions had cut its crude exports from a peak of 2.5 million bpd before 2011 to just over 1 million bpd in recent years.