Production of companies at the inter-Korean industrial complex in North Korea exceeded $500 million last year for the first time since its opening in 2004, the government said Sunday.

According to the Unification Ministry, a total of 124 South Korean factories operating in the complex produced $515.49 million worth of goods in the first 11 months of last year, up more than 20 percent from the previous year and the highest yearly output even excluding the December tally.

The figure for the entire year is estimated to reach $560 million, given that their monthly production averaged around $50 million in the year, it said.

"The Gaeseong Industrial Complex managed to grow stably, recording more than a 20 percent increase in total output despite North Korea's shelling in August across the border and various other incidents in and out of the country," a ministry official said.

There were 54,763 North Korean workers and 803 South Korean managers at the factories in the industrial park located in the North's border city of Gaeseong as of November.

North Korea fired shells at a South Korean front-line military unit in the western part of the heavily fortified border on Aug. 20, prompting the South to fire back. (Yonhap)