LGBT activists have termed the move as a setback.

The court said same-sex relationships could harm troops' combat readiness and undermine discipline, reported BBC.

However, same-sex intercourse between civilians is not a crime in the country.

In South Korea, serving in the military is compulsory as people aged between 18 to 28 are required to serve for 20 months.

Responding to the Constitutional Court of Korea’s decision to uphold for the fourth time Article 92-6 of the 61-year-old Military Criminal Act, which criminalizes consensual same-sex sexual acts in the military constitution, Amnesty International’s East Asia Researcher Boram Jang said:  "This continued endorsement for the criminalization of consensual same-sex acts within the Korean military is a distressing setback in the decades-long struggle for equality in the country. This ruling underscores the widespread prejudice experienced by LGBTI people in South Korea and the government’s lack of action to prevent harm and ensure equality which is their human rights responsibility."

“Article 92-6 has institutionalized discrimination, reinforced systematic disadvantages faced by LGBTI people and risked inciting or justifying violence against them, both inside the military and in everyday life. It has no place in Korean society and should be scrapped immediately," Jang said.