A South Korean triathlete took her own life after enduring years of physical and verbal abuse from coaching staff and having her complaints to sporting authorities allegedly ignored, according to reports.

Choi Suk-hyeon, 22, who won bronze in the junior women's event at the 2015 Asian triathlon championships in Taipei, reportedly died at her team dormitory in Busan last month.

According to widely-circulated screenshots of her last text message conversation with her mother, she begged her to "lay bare the sins" of her abusers.

The South is a regional sporting power and regularly among the top 10 nations in the medal table at summer and winter Olympics.

But in an already intensely competitive society, winning is virtually everything in its sports community -- and physical and verbal abuse are known to be rife.

Choi came fourth in the 2016 national championships elite women division but failed to fulfil her early promise, dropping to 14th in the same contest last year.

On one occasion, Choi wrote in her journal: "It was raining today and I was beaten so bad... I am shedding tears every day."

Multiple reports in South Korean media say Choi compiled audio recordings of physical abuse.

In one file broadcast by cable news station YTN, her coach was furious she had put on weight: "You have to avoid eating for three days," he said. "You promised me you would take responsibility."

Then he told her: "Clench your teeth," followed by sound of a sharp slap.

Team officials forced her eat 200,000 won-worth ($166) of bread as punishment for failing weight control and habitually beat her, said the reports.

Choi complained to the Korean Sport and Olympic Committee (KSOC) in April seeking an investigation.

But an acquaintance told Yonhap news agency that she "sought help from many public institutions but everyone ignored her pleas".

KSOC denied it had ignored her complaint, stating in a press release it had assigned a female investigator after receiving Choi's plea in early April. 

It promised to take "stern measures" against those involved, expressing "profound regret" over the incident. 

Prosecutors were now looking into the case, it added.

A petition posted on South Korea's presidential office website Thursday demanding a thorough investigation had more than 5,000 signatures by mid-morning.

Last year, double Olympic gold medal-winning short-track speed skater Shim Suk-hee went public with accusations her former coach sexually molested and physically abused her multiple times. 

The coach was jailed for 10 months.