The number of illegal immigrants in South Korea surpassed the 210,000 mark last year, three times the total reported for neighboring Japan, government data showed Tuesday.

Illegal immigrants living in South Korea reached 214,187 last year, according to the Ministry of Justice. Corresponding figures for Japan stood at 62,818.

The number of illegal immigrants has been increasing steadily from 183,106 in 2013 to 208,778 in 2014, along with the number of tourists who visit the country using the no-visa entry program.

South Korea's resort island of Jeju, which actively runs the program, saw the most dramatic increase in the number of illegal aliens.

Under the special act for Jeju island, all visitors except for nationals from terrorism-linked countries can enter and stay on the resort island without a visa for up to 30 days if the purpose of their stay is tourism.

The number of tourists visiting the island increased from 1 million in 2011 to 1.81 million in 2013 and 2.62 million in 2015, according to the data. In 2015, Chinese nationals accounted for 85.3 percent of the total.

The number of tourists using the no-visa program also soared from 113,825 in 2011 to 429,221 in 2013 and 629,724 last year.

The number of illegal aliens on the island increased from 282 in 2011 to 731 in 2013 and 4,353 last year. The latest figure is also a dramatic change from 1,450 reported in 2014.

Still, the detection rate remained at 29 percent on average from 2010 to 2014, according to the data.

In January, a group of Vietnamese tourists who visited South Korea without visas disappeared from the resort island, causing alarm bells to go off. Out of the 59 Vietnamese who fled, 23 are still missing.

"Through collaboration with related bodies, we will crack down on illegal immigrants on the island," said Kim Han-soo, a senior prosecutor at the Jeju District Prosecutors' Office. (Yonhap)