The complex in the town of Kaesong in North Korea, close to the border with South Korea, began a trial-run production with the two sides discussing ways to ensure sustainable growth of the jointly run venture, Yonhap News reported.
Monday's restart is expected to lead to full resumption of operations at the 10-year-old facility, where 123 South Korean companies are represented, providing jobs to thousands of North Koreans and an important source of foreign exchange for the isolated Communist country.
The industrial park has been closed since April when tensions on the Korean Peninsula were at their worst, resulting from North Korea's third nuclear test in February. Operations stopped after North Korea unilaterally pulled its 53,000 workers from the complex, citing political and military provocations from South Korea, Yonhap said.
Intense negotiations to resume operations there had been going on in recent months as the political environment improved.
South Korean officials said 821 South Korean managers and workers had planned to cross the border over to Kaesong Monday and more than 400 of them planned to stay overnight to oversee normalization of production there, Yonhap reported.
The resumption of operations came after the two sides agreed last week to set up safeguards to ensure the complex will not be shut down again due to non-economic reasons.
They agreed to create a dispute arbitration panel and to hold international investor relations sessions to promote the participation of other countries in the complex.