Illegal foreign exchange transactions jumped 54.3 percent in 2014 from two years earlier mainly due to more stringent screening by authorities, the customs service said Monday.

The Korea Customs Service said it detected 6.73 trillion won ($6.17 billion) in illegal cross-border movements of money last year, compared with 4.36 trillion won tallied in 2012.

Despite the jump in the amount involved, the number of cases stood at 1,640, a modest gain of 1.3 percent from 1,618 reported two years earlier.

"The total number of detected cases edged up, although there was a trend among some to try to move more money than in the past," a KCS source said.

The customs agency, along with the Financial Supervisory Service, ran a program from August to November 2014 to crack down on price fixing for both exports and imports, as well as efforts by some to hide their wealth abroad, he said.

Some companies attempted to bring money earned abroad to South Korea by disguising it as third party investments or donations, while others tried to ship funds abroad by claiming they paid more for a product then they really did, the official added.

The KCS said it plans to work with other government agencies this year to clamp down on unreported foreign exchange transactions, with particular emphasis placed on keeping close tabs on trading. (Yonhap)