One of South Korea's small and mid-sized manufacturing companies (SME) at the inter-Korean industrial complex has applied for business closure due to falling sales, officials said Thursday.

Around 120 South Korean firms, mostly SMEs, have been operating at the Kaesong Industrial Complex, employing around 53,000 North Korean workers.

The North abruptly suspended operation of the industrial part in April last year, citing tensions on the divided peninsula before resuming it in September that year.

An unidentified small manufacturer for watch and mobile phones cases on Wednesday submitted an application for dissolution to the committee handling affairs at the joint park, according to officials from Seoul's unification ministry.

It marked the second case since June 2009 that South Korean firms operating at the Kaesong Complex have closed their businesses. It also marked the first time since the operation of the park had been halted briefly last year. 

The company, which had employed about 100 North Korean workers, has been suffering from business setbacks since 2012 as its annual sales fell to US$300,000 from its peak of some $700,000.

The industrial complex opened in the early 2000s in the North's border city of Kaesong, the last remaining symbol of inter-Korean reconciliation. It has served as a major revenue source for the cash-strapped communist country. (Yonhap)