South Korea's tax agency said Wednesday that it has launched an investigation into 23 businesses and individuals suspected of evading taxes through paper companies established in tax haven regions. 

The National Tax Service added that it has completed a probe into 83 offshore tax evasion cases, which led to collecting about 479.8 billion won ($424.6 million) in additional taxes.

The move is part of pan-governmental efforts to push for fair tax justice and expand the overall revenue base for growing demand for fiscal spending. Cracking down on tax evasion and regulating the underground economy were part of the efforts. 

"(We) will consistently and steadily seek to regulate the underground economy not just to meet the fiscal demand but also to boost social cohesion by strengthening tax justice," an NTS official said.

Some of those under investigation are suspected of either not reporting or disguising their income by using secret financial accounts in Switzerland or paper companies in tax haven regions.

Most of them have allegedly used the Virgin Islands, Hong Kong, Panama and Singapore to evade taxes, the NTS explained.

Offshore tax evasion has been brought into spotlight since a non-profit organization set up by former journalists recently disclosed names of high-ranking business people and their families who have allegedly run paper companies in tax haven regions in an apparent bid to evade taxes. 

The NTS did not confirm whether they are included in its ongoing probe but the possibility remains open that some large businesses could be part of its investigation.

Of the 23 people subject to the ongoing investigation, 15 are corporate entities, while eight are individuals, according to the NTS. The tax agency said that they include some high-profile business entities. (Yonhap News)