The smuggling happened from March 2015 and the gold came from Tokyo and China's Yantai.
Korea's gold price is reported to be higher than other countries because of the 15 per cent tax imposed on the metal.
"Gold smuggling is a business people can make money easily from because of the price gap," an official at the Korea Customs Service (KCS) has said.
"As our crackdown gets tougher, smugglers are also getting more sophisticated in hiding gold or other jewellery products they want to bring in."
He went on to say the KCS was preparing to launch a special task force to bring an end illegal gold smuggling.