Illegal trade detected by customs authorities surpassed the 9 trillion-won ($7.66 billion) mark in 2014, fueled mainly by money laundering schemes and transactions aimed at hiding assets abroad, a report showed Thursday.

According to the report by the Korea Customs Service provided to Rep. Park Myung-jae's office ahead of the annual parliamentary audit of the government, the total sum of uncovered illegal trade reached 9.24 trillion won last year, up 5.7 percent from 2013.

Data showed that there has been a steady increase in illegal trade with the total caught in 2011 standing at 5.91 trillion won, with this number rising to 6.52 trillion won the following year.

Of the total, 6.72 trillion won worth of illegal trade involved money laundering and transactions designed to transfer and hide assets abroad. This was followed by smuggling activities that accounted for 1.15 trillion won.

Improper reporting of transactions and products that violated country of origin rules made up 693.6 billion won worth of illegal trade, with counterfeit items and those that violated international intellectual property rights reaching 516.2 billion won.

The report also showed illegal narcotics trafficking that was intercepted reached 150.4 billion won last year. This represents a 70 percent spike from the year before.

Of all violations, 1,838 were related to customs laws, with the breaking of the country's foreign exchange rules coming in second at 1,640 cases. It said illegal drug trafficking violations reached 308 cases.

The customs office said the recent increase is the result of South Korea's expanding trade volume and the government's clamp down on the underground economy.

Besides a rise in illegal trade, there has been an increase in rewards given to people who provide vital information on unlawful activities.

The customs office said as of last year it gave 970 million won in reward money for information on illegal trade, up from 918 million won the previous year.

"Data clearly showed that illegal trade is becoming more organized and large scale, that makes it imperative for authorities to have better intelligence gathering capabilities," the lawmaker's office said. (Yonhap)