A transgender soldier in South Korea says she will sue the military after it announced its intention to dismiss her for undergoing gender confirmation surgery.

Key points: The army said in a statement the surgery left Staff Sergeant Byun unable to continue to serve

The army said in a statement the surgery left Staff Sergeant Byun unable to continue to serve Staff Sergeant Byun said she suffered from depression prior to her gender confirmation surgery

Staff Sergeant Byun said she suffered from depression prior to her gender confirmation surgery Rights activist Lim Tae-hoon said he "can't resist feeling wretched at the military's vulgar mindset"

It is the first time in South Korea that an active-duty member has been referred to a military panel to determine whether to end his or her service due to surgery related to gender transition.

South Korea prohibits transgender people from joining its military but has no specific laws on what to do with those who have sex reassignment operations during their time in service.

Byun Hui-su, who holds the rank of staff sergeant and is stationed in Gyeonggi Province, north of Seoul, had the operation in Thailand last year while on leave and had expressed hope of continuing to serve in the female corps.

The army said in a statement that it concluded the soldier's operation could be considered a reason for discharge.

It said the decision went through due process and was based on a related military law on personnel changes.

Army officials cited a provision of the law allowing the military to discharge personnel with physical or mental disabilities if those problems were not a result of combat or in the line of duty.

South Korean army Sergeant Byun Hui-su said it was a extremely difficult decision to let her base know about her identity. ( AP: Ahn Young-joon )

In her first public appearance since her case was publicised last week, Staff Sergeant Byun said she would pursue a lawsuit against the army, all the way to the country's highest court if necessary.

"I will continue to fight until the day I can remain to serve in the army," she said.

"I'll challenge the decision until the end, to the Supreme Court."

'Depression got too severe'

The army said in a statement that while it will make efforts to protect soldiers' human rights and prevent discrimination, the surgery left Staff Sergeant Byun unable to continue to serve.

Staff Sergeant Byun broke down in tears as she described the decision to undergo surgery after suffering from gender dysphoria — distress from the internal conflict between gender identity and the sex assigned at birth.

"It was an extremely difficult decision to let my base know of my identity, but once I did, I felt much better," she told reporters at a news conference in Seoul after the military announced its decision.

"I thought I would finish serving in the army and then go through the transition surgery and then re-enter the army as a female soldier. But my depression got too severe."

The army said in a statement that it concluded the soldier's operation could be considered a reason for discharge. ( AP Photo/Lee Jin-man, File )

One army official with knowledge of the deliberations told Reuters there should be no reason for the military to deny Staff Sergeant Byun if she reapplied to serve in the female corps after completing the legal process to formally become a woman.

A human rights organisation had filed a petition with a national human rights watchdog urging the army to postpone its decision until after the Staff Sergeant had completed the court process, but the army said that legal proceeding was irrelevant to its personnel decisions.

The case has triggered debate over the treatment of transgender troops and soldiers from the wider LBGT community in the country, which requires all able-bodied men to serve for around two years.

Staff Sergeant Byun said becoming a soldier was her childhood dream and that she wanted to serve at the tense border with rival North Korea.

She said she still hoped to serve in the military in the future.

"Apart from my gender identity, I want to show everyone that I can also be one of the great soldiers who protect this country."

'Military's vulgar mindset'

Speaking at the same news conference, rights activist Lim Tae-hoon said he would fight alongside Staff Sergeant Byun and others to transform what he called "our savage military."

Mr Lim, the leader of the Seoul-based Centre for Military Human Rights, took issue with the army's legal justification for discharging Staff Sergeant Byun.

"I can't resist feeling wretched at the military's vulgar mindset as they determined that the lack of a male genital is a physical disability," he said.

South Korea's state-run human rights watchdog recommended on Tuesday that the army postpone its decision.

The National Human Rights Commission said in a statement that referring the soldier to the military panel would be an act of discrimination over sexual identity and affect the soldier's basic human rights.

Public views on gender issues in South Korea have gradually changed in recent years.

Several gay-themed movies and TV dramas have become hits and some transgender entertainers have risen to stardom. However, a strong bias against sexual minorities still runs deep in South Korean society.

Activists say transgender people are likely to face harassment, abuse and insults and many suffer from depression.

Reuters/AP