Exports rose to a provisional $24.72 billion in September from $20.83 billion a year before, while imports increased 24.5 percent to $22.65 billion from $18.19 billion, the commerce ministry said in a statement.

The annual exports growth was the highest since a 26.5 percent rise in November last year and compared with the median forecast from a Reuters poll of eight economists for a 15.1 percent gain. Imports had been forecast to grow 20.6 percent.

Sharp growth in mobile phone exports amid the recovering global information technology industry led the month's total sales abroad, more than offsetting a drop in auto exports due to strikes by unionised workers, the commerce ministry said.

It did not give detailed export figures by product.

Unionised workers at the country's top auto maker, Hyundai Motor Co Ltd, and its affiliate Kia Motors Corp had stopped work for several hours each day between late August and early September.

Investors have been anticipating the first rise in South Korean interest rates since May 2002 as early as this month after the central bank governor said in September that a rate rise would be seriously considered at an October 11 policy meeting.