The current account figure for December was $2.14 billion.
The Bank of Korea said tech and petrochemical product exports in January remained firm despite a rising won.
"The surplus is likely to be smaller for February but the country is expected to see the underlying trend of surplus," Cho Yong-seung, director of the bank's monetary and financial statistics division, told a news conference, Yonhap News reported.
There have been concerns a weaker Japanese yen could adversely affect South Korean exports by making them more expensive in markets where the countries' products compete. Exports account for about half of the South Korean economy.
The South Korean won has lately appreciated about 5 percent against the yen.
"The won's ascending trend is feared to crimp Seoul's exports as its impact on overseas shipments will be felt with a time lag," economist Lee Sang-jae at Hyundai Securities Co. told Yonhap. "Korea's exports growth will hinge on how fast global demand would pick up."
Last month, the Bank of Korea said it expects the current account surplus for 2013 to reach $32 billion.