Police in South Korea are looking for five Vietnamese women who allegedly paid some locals a fee to help them enter the country illegally.
Three Korean men were arrested Wednesday for their roles in the scheme, The Korea Herald reported.
Initial investigation found the women, all in their early 20s, each paid the men a brokering fee of 1.5 million won ($1,300) so the men could help them obtain hospital registration forms to apply for visas for medical treatment.
The women reportedly arrived in August last year but have since never showed up for any medical procedures registered.
In a separate case, three people in Hanoi are being investigated for allegedly running a human smuggling ring that sent dozens of Vietnamese to South Korea to work illegally in January.
The Vietnamese arrived as tourists but 59 of them then disappeared from the tour. The Korean government has deported 34 so far.
According to the Korea Tourism Organization, around 170,000 Vietnamese tourists visited the country last year, with 4,353 of them reportedly leaving their tour and illegally staying on Jeju Island.
In 2011, there were only 282 cases.