Offices of the country’s largest discount chain E-Mart were raided by labor authorities Thursday on suspicions that the company violated labor laws to prevent employees from joining a labor union.

“It was confirmed that there were a number of problems regarding issues uncovered in the recent special labor audit,” an official at the Seoul office of the Ministry of Employment and Labor said.

In a labor audit conducted last month, evidence emerged that Shinsegae Group’s discount store placed workers under illegal surveillance.

The official said that the E-Mart headquarters, six branches, two labor consultant firms and the homes of a number of employees were searched as the discount chain operator has been avoiding submitting materials required for the investigation.

Materials taken by the labor office include account books, minutes of internal meetings and electronic data.

“The investigation is being conducted, and officials have been summoned for questioning. A two-track investigation ― special labor audit and the investigation into unfair labor practices ― will be conducted.”

The labor ministry will conduct a special labor audit on 24 E-Mart branches across the country until Friday.

By Choi He-suk  (cheesuk@heraldcorp.com)