The largest money-laundering scam conducted through overseas tax-havens has been uncovered by the Korea Customs Service.

According to reports, the Korea Customs Service uncovered a money laundering scam by a local intermediate trading firm involving foreign currencies valued at 762.5 billion won ($704.1 million).

The company imports petrochemical products, which it then exports to other markets. The value of illegal transactions is reported to have accumulated over a period of five years.

The value of the company’s illegal dealings is the largest to have been uncovered since 2007 when the tax authorities began to probe such dealings occurring through known tax-havens.

The company, whose case is now under investigation by the Seoul Central District Prosecutors’ Office, is reported to have set up a paper company in Hong Kong and Singapore to be laundered and deposited outside of Korea.

According to reports, the paper company in Hong Kong was set up under the name of a third party, and papers were drawn up to make it appear that the company was conducting intermediate trading businesses.

The Korea-based firm’s profits were transferred to the Hong Kong-based paper company, which then transferred the funds to accounts held by another paper company based in Singapore.

The Korea Customs Service, however, was unable to confirm the value of illegal transactions.

“The case was referred to the prosecutors’ office only recently, so the final course of action has not been finalized,” an official at the Korea Customs Service’s public relations department said.

“The amount is also unclear since the customs service did not officially disclose related information as the case is still ongoing.”

By Choi He-suk  (cheesuk@heraldcorp.com)