Law enforcement officers chasing illegal foreign workers has become more common across the country this year.

Immigration authorities are strengthening efforts to reduce the number of illicit migrant laborers, which was estimated to exceed 167,000 as of the end of 2011.

The proportion of illegal workers in the total expatriate workforce increased from 24 percent in 2010 to 29 percent last year.

Officials at the Korea Immigration Service, an agency affiliated with the Justice Ministry, are concerned that the number of illicit foreign workers will further grow this year as many of the 67,111 expatriates whose employment period is set to expire in the coming months may slip through the formal regulatory system.

A senior KIS official said the office aims to reduce the proportion of illegal migrant laborers to below 20 percent by the end of the year.

Their growth will disturb local labor markets and hamper the implementation of the employment permit system introduced in 2004 to allow documented expatriates to work here for up to 58 months.

Some civic groups have taken issue with what they claim is an oppressive way of arresting illegal foreign workers.

In a 2011 survey by the National Human Rights Commission of 288 expatriates captured for illegally working, 80 respondents insisted law enforcement officers infringed on their human rights in the process of taking them into custody.

The Justice Ministry, however, rebuffed the claims, saying its officials have been adhering to strict rules in rounding up illegal foreign laborers.

“It may be more efficient to toughen punishment for employers who hired illicit workers,” said Seol Dong-hoon, professor of sociology at Chonbuk National University in Jeonju, North Jeolla Province.

By Kim Kyung-ho (khkim@heraldcorp.com)