South Korean lenders have seen a rise in counterfeit $100 bills in the first seven months of the year following the release of the redesigned denomination with bolstered security features, data showed Tuesday.

The worth of fake U.S. notes found at seven local banks reached $73,143 in the January-July period, compared with $47,576 the previous year, according to industry data. Most of the counterfeit bills in circulation were $100 bills, which are the highest denomination in the U.S. currency system.

Korea Exchange Bank, which leads the country's foreign exchange market, found $57,480 worth of counterfeit notes in the seven-month period, more than double the amount it detected last year.

Other lenders -- such as Hana, Woori and Shinhan -- all saw the amount of counterfeit bills surpass last year's total, according to the data.

The on-year rise follows the release of new $100 banknotes. The U.S. Federal Reserve began circulation of the redesigned bills with anti-forgery features such a 3D security ribbon and portrait watermark in October.

Experts said the release may have stoked circulation of fake $100 bills that had been manufactured ahead of the redesign.

They also cautioned that counterfeit Chinese renminbi bills may trend higher as economic ties between Seoul and Beijing build up.

The seven lenders saw the amount of counterfeit renminbi notes reach $9,765 yuan in the first seven months of this year.

In contrast, the number of counterfeit South Korean banknotes has been falling over recent years. The number of fake bills reported to the central bank reached 3,585 last year, compared with 8,627 the previous year, according to the Bank of Korea.

The number of fake bills per 1 million bank notes reached 0.9 for Korea last year, trailing Japan with 0.2 at the end of 2012.

In comparison, Australia found 10.2 fake bills per 1 million bank notes, followed by Canada with 28 and Mexico with 33.7. The number of such bills reached 253.7 for Britain. (Yonhap)