SEOUL (AFP) - South Korea's current account surplus narrowed slightly in April, but strong car and steel exports kept it in the black for the 26th straight month, the central bank said Thursday.

The April surplus stood at US$7.12 billion (S$8.9 billion), down 2.2 per cent from a revised US$7.29 billion in March, the Bank of Korea (BOK) said.

Compared with a year earlier, the surplus was up 56.5 per cent from US$2.57 billion.

Asia's fourth-largest economy posted an all-time high surplus of US$79.88 billion in 2013.

The current account is the broadest measure of cross-border trade.

The service account, which includes outlays by South Koreans on overseas trips, logged a US$1.04 billion deficit last month, up from a revised shortfall of US$647.8 million in March.