South Korea formally condemned North Korea Monday for unilaterally revising regulations on the minimum wage for its workers at an inter-Korean industrial complex in the North's border town of Kaesong.

At the weekend, the North announced its decision to remove the 5-percent on-year cap for wage increases for its 53,000 workers at the Kaesong Industrial Complex.

"It is regrettable that the North has violated the inter-Korean agreement on the operation of the joint venture," unification ministry spokesman Lim Byeong-cheol said at a press briefing.

As the South and the North have agreed to improve the wage system for the development of the complex in accordance with international standards, the two sides should handle the issue through bilateral consultations, he said.

The North's authorities have not informed the South directly of its decision on the matter, he added.

The South's government will take appropriate measures after talking with North Korean officials and gathering details of its next step, said Lim. 

Under the inter-Korean deal, wage increases for the North's workers in the Kaesong complex should not exceed 5 percent from a year earlier.

Their wages have jumped 5 percent every year since 2007. North Korean workers are currently paid US$70.35 each month. If various allowances and incentives are counted, wages reach $130, reportedly about 50 percent higher than the average income of workers in North Korea.

More than 120 South Korean firms, mostly small and medium enterprises, operate in the Kaesong facilities located just north of the inter-Korean border.

The complex, created in 2004, is designed to combine the North's cheap labor and the South's capital and technology. (Yonhap)