The daughter of the chairman of SK Group, South Korea's third largest business conglomerate, is serving with a naval unit defending South Korea's sea border with North Korea, a military source said Tuesday.

Chey Min-jung, the second daughter of Chey Tae-won, was commissioned as a naval officer in November 2014 and has since taken part in the Navy's anti-piracy mission off the coast of Somalia last year.

"Lieutenant Chey has been posted to the headquarters section of the frontline unit under the 2nd Fleet," a military source said.

The fleet is responsible for guarding the Northern Limit Line (NLL) that forms the western sea demarcation line between the two Koreas.

Because of several clashes along the NLL, including the sinking of a South Korean Navy corvette that left 46 sailors dead in March 2013, the fleet maintains a high level of readiness.

The source said that Chey has been assigned a role as an intelligence and communications officer under the squadron commander, who controls several combat vessels. He said the lieutenant's duties include passing on orders from the commanding officer to vessels.

"She, moreover, accompanies the commander on patrol and training missions to the NLL," the insider added.

The Navy said that Chey does not want to receive attention because she is the daughter of the head of one of South Korea's biggest business conglomerates, and has faithfully fulfilled her duties as an officer.

The 24-year-old Chey, also the granddaughter of Roh Tae-woo, the general-turned-president who led the country from 1988 to 1993, is the first woman from a conglomerate family to enlist in the military in a country where sons of the privileged are often caught dodging the mandatory military service.

In South Korea, all able-bodied young men are subject to compulsory military service for about two years. Women, on the other hand, are exempt from the duty, though they can volunteer. (Yonhap)