Korea's Ministry of Justice / Newsis

Four in 10 foreigners who illegally stayed in Korea last year entered the country without visas and stayed beyond the visa-free period, data from the justice ministry showed Saturday.

The number of illegal aliens in Korea came to 423,675 as of the end of last year, accounting for 16.9 percent of the total foreigners staying in the nation, according to the data cited by Rep. Song Seong-jun of the ruling People Power Party.

Of the illegal aliens, the number of those who arrived in Korea without visas reached 190,000, or 44.9 percent. Foreigners are allowed to enter Korea without visas in cases of visa exemption (B-1) and tourists in transit (B-2).

The number of illegal aliens who entered Korea with a visa waiver came to 169,000, the largest proportion for a single category at 40 percent, followed by those with a short-term stay visa at 87,000. Those with B-2 status reached 21,000, the data showed.

Such foreigners are believed to be illegally staying in Korea to engage in economic activities without proper employment visas.

By nationality, the number of Thais who illegally stayed in Korea reached 145,000, the largest share at 76.3 percent, followed by Chinese with 15,000 and people from Kazakhstan with 11,000, the data showed.

The government suspended visa waiver programs with Pakistan in 2001 and Bangladesh in 2008, citing a sharp rise in illegal aliens from those nations. (Yonhap)