It marked the largest on-year increase since the 220,000 people recorded in April 2002.

Of the total, one-man operations, which don't hire workers, numbered 3.95 million in February, 137,000 more than a year earlier. The increase also represented the steepest increase since March 2002.

Watchers said the number of one-man operations surged in February as more people set up restaurants and other businesses amid difficulty landing jobs due to the country's economic sluggishness.

"Many people left jobless by a recent corporate restructuring drive and retired baby boomers choose to set up mom-and-pop stores as they find it hard to be rehired," said professor Kim Kwang-suk, who teaches at Hanyang University in Seoul.

South Korea's economy, Asia's fourth largest, has remained in the doldrums in the wake of weak exports and stubbornly low domestic demand.

Industry watchers warned that one-man operations are suffering from sluggish sales and could bear the brunt of a possible rise in bank lending rates as most self-employed people rely on loans to start businesses.

According to the statistical agency, the largest percentage of the country's self-employed (30.6 percent) registered annual sales of 12 million won to 46 million won, with the top line of another 21.1 percent hovering below the 12 million-won mark.

In contrast, the country's self-employed are highly leveraged.

According to a central bank report, their debt totaled 480.2 trillion won as of end-2016, up 13.7 percent from a year earlier. (Yonhap)