The National Tax Service (NTS) has launched investigations into 224 individuals suspected of being tax dodgers, including loan sharks and entrepreneurs.
The agency is currently investigating 51 owners of large fortunes, 48 suspects of offshore tax evasion, 117 private moneylenders and eight others thought to have evaded taxes using Internet cafes.
The agency has mobilized nearly 1,000 personnel over the past month for the investigation.
"We have made the normalization of the underground economy our highest priority," Lim Man-soo, assistant commissioner of the investigation planning division of NTS, told reporters at the agency's headquarters in downtown Seoul.
"We plan to execute strong investigations on the four areas that many believe are the most likely to evade taxes and as of today have deployed 927 investigators." The NTS added 400 investigators to its regional offices and formed 70 new teams.
He said the nationwide probe was added to the service's annual investigations following the inauguration of the new government. It is the first large-scale investigation under the new commissioner of the NTS, Kim Duk-joon, who took office March 27.
It is also the largest investigation this year, followed by one on 66 people suspected of tax evasion through the distribution of fake petroleum in February.
Residents with high incomes and owners of large companies are highest priorities for the NTS in 2013.
The agency expressed serious concern about a new type of tax evaders who use Internet cafes. It said the spread of smartphones and new transaction methods enabled by the development of information technology has made some online communities a hub for shadow economies, and is looking into eight cafes. "Last year we found 250 to 260 cases," Lim said.
The agency also announced measures to ease up on small- and medium-sized companies, in line with the Park Geun-hye administration's plan to relax regulations on them.
To help small- and mid-sized firms, it will as a rule not investigate companies with annual revenue lower than 10 billion won ($8.8 million). For companies that exceed that amount but are socially responsible, that fact will be taken into consideration before an investigation.
In contrast, companies with over 50 billion won in annual revenue will be "scrutinized intensively" for possible tax evasion.
The latest move by NTS is in line with Park's initiative to normalize the shadow economy and expand the tax base to finance her welfare budget.
Last year, the NTS investigated more than 771 owners of large fortunes and collected 1.1 trillion won in unpaid taxes.
The tax agency also won major cases against offshore tax evaders. It investigated 202 people suspected of such last year and collected 825 billion won. It cooperated with authorities in Switzerland then and will do so again this year, the agency said.
"We've widened our global cooperation and our networks to detect tax evasion increased last year," Lim said. "However, methods of evasion are becoming increasingly sophisticated."