K-pop girl group (G)I_DLE's Soojin has refuted allegations that she was a bully in middle school, which in South Korea would be from about 12 or 13 to 15 or 16.

The 22-year-old singer was accused last Saturday (Feb 20) on social media by a former classmate and her older sister of being a teenage bully.

She was said to have slapped her former classmate, tried to rally others in a group chat to make her an outcast and taken other classmates' money and belongings.

On Monday, Soojin posted her rebuttal on the fan platform U Cube: "When I was a student, I always stood out and it's true that bad rumours always followed me around."

While she admitted to trying out cigarettes and dressing inappropriately in middle school, she roundly denied all other accusations of bullying and claimed that she and her former classmate had just drifted apart after an argument.

Actress Seo Shin-ae, 22, was dragged into the controversy, as she had attended the same school. A separate anonymous post earlier this month had alleged that she was also subject to bullying from Soojin, who denied it, stating she had never even spoken to Seo.

On Monday, Seo posted a cryptic message on Instagram Stories in English: "None of your excuse (sic)."

However, she has now been subject to harsh criticism on social media from Soojin's fans, who have flooded her comments.

Seo hit back by posting the song Therefore I Am by Billie Eilish.

Lyrics from the song include "I'm not your friend, or anything", "Get my pretty name out of your mouth" and "Don't talk 'bout me like you might know how I feel".

After Soojin made her public denial, the original accuser's sister has come out with another statement, promising more details: "Yes, we'll be writing. Since she can't remember."