The case comes just a month after the country's air force chief resigned over the suicide of a master sergeant who was sexually assaulted by a colleague.

She reported the case higher up the chain of command, only to have her complaints ignored, and took her own life in May.

That sparked a national outcry in South Korea, which maintains a conscript army to defend itself against the nuclear-armed North.

In the latest case, the brigadier-general reportedly attempted inappropriate physical advances to a subordinate after a dinner with other soldiers.

Appropriate action will follow after a "thorough probe" into the arrested officer, defence ministry spokesman Boo Seung-chan said.

The military would provide "legal and institutional assistance" to the victim, he added.

Amid intense criticism over the handling of the air force abuse case, officials asked for complaints of sexual abuse to be submitted in June, and have reportedly launched investigations into around 20 other allegations.

The short time interval between the two cases prompted accusations the military was failing to prevent sex crimes.

"At this rate, it now appears the principal enemy of female soldiers is not North Korea, but male superiors," one user posted on Naver, the country's largest portal.

South Korean society remains socially conservative despite its rapid rise into an industrial powerhouse, and sexual harassment victims often face pressure to stay silent for fear of public shaming.

But signs of change emerged after the country's own #MeToo movement, sparked in 2018 by prosecutor Seo Ji-hyun, who publicly accused a superior of groping her at a funeral, prompting many others to share their stories.