South Korea's current account surplus widened to a four-month high in March as exports gained ground despite the yen's weakness and the service account improved, the central bank said Monday.

The current account surplus reached US$4.98 billion in March, up from $2.71 billion the previous month, according to the Bank of Korea (BOK). The current account is the broadest measure of cross-border trade.v The March reading was the largest since November last year, marking the 14th straight month of a surplus run.

The data came even as the yen's weakness is feared to sap Seoul's exporters as it boosts price competitive edges for Japanese rivals. The Korean won has risen more than 20 percent against the yen since November.

But BOK Gov. Kim Choong-soo said last week that the yen's weakening trend is likely to persist for a long time, expressing concerns that its negative impacts on Korea's exports will become visible down the road.

In March, Korea's goods balance posted a surplus of $4.21 billion, up from $2.56 billion surplus in February.

Last month, exports rose 1.3 percent on-year to $47.99 billion while imports fell 1.5 percent to $43.78 billion.

The service account, which includes outlays by South Koreans on overseas trips, posted a surplus of $905.2 million last month, a turnaround from a shortfall of $461 million the previous month.

The primary income account, which tracks wages for foreign workers and dividend payments overseas, logged a shortfall of $222.3 million in March, compared with a surplus of $628.9 million in February.

In March and April, offshore investors usually repatriate dividend payments by Korean companies that close their books in December, crimping the country's income account balance.

Meanwhile, the capital and financial account, covering cross-border investments, posted a net outflow of $6.81 billion last month, compared with a net outflow of $3.31 billion in February, the central bank said.

In April, the BOK slightly revised up the 2013 current account surplus estimate to $33 billion from $32 billion. Last year, Korea's current account surplus reached a record high of $43.14 billion.