HONG KONG (AFP) - A top Hong Kong hurdler on Thursday (Nov 30) accused her former coach of sexually assaulting her when she was a schoolgirl, prompting the city's leader Carrie Lam to ask police to look into the matter.

Lui Lai Yiu is the first high-profile woman in socially conservative Hong Kong to tell of abuse as part of the #MeToo movement exposing sexual misconduct.

In an open letter posted on Facebook on her 23rd birthday, Lui did not name the man who abused her as a young teenager, calling him "coach Y".

She recalled how, as a young teenager, she had thought nothing of it when he offered her a massage at his home to relax her muscles.

After starting with her jeans on, he eventually removed them and her underwear and touched her private parts, she said.

"In my mind he was a coach I respected," wrote Lui.

"I had never thought he would do despicable things to his students."

Mrs Lam, the city's first female chief executive, told reporters she was "very upset" to learn about the abuse.

"The police chief will certainly follow up in earnest," she said, urging other victims to come forward "as difficult this experience is" so that allegations could be investigated.

The #MeToo campaign exposing sexual misconduct spread rapidly in October after multiple allegations against Hollywood movie mogul Harvey Weinstein and has since shaken artistic, media and political circles globally.

Pui Ching Middle School, which Lui attended, said in a Facebook statement on Thursday that after Lui told them three weeks ago of her intention to publicise the incident they had immediately stopped working with the accused coach.

The Hong Kong Amateur Athletic Association expressed "deep regret" over the incident and said it takes a "zero tolerance" approach to abuse. Police gave no comment when asked by AFP whether an investigation was underway.

Lui is a promising athlete who took the gold in the 60-metre women's hurdles at the Asian Indoor Games in September.

She said she was inspired to speak out by American Olympic gold-winning gymnast McKayla Maroney, one of a number of women who accused former USA Gymnastic team doctor Lawrence Nassar of abusing them.

Nassar, 54, has pleaded guilty to multiple counts of criminal sexual conduct.

Lui shared Thursday's post with a photo of her holding a sign that read "#METOO" with her initials "LLY" and her eyes cropped out of the shot.

Having only confided to a close friend for the first time two years ago about the incident, Lui said she wanted to speak up on her birthday as a gift to herself, as well as to raise awareness about child sex abuse and to encourage other victims.

"To speak the truth is a form of liberation, to turn myself from victim to survivor," she wrote.

"It was not my fault, nor my parents', nor my school's. It was the perpetrator's fault," she said.

Messages of support followed her post, in which she called for the #MeToo movement to keep going.

Rights group and crisis centre The Hong Kong-based Association Concerning Sexual Violence Against Women urged the public to use the hashtag #MeTooHK this month in a bid to increase the movement's resonance in the city, where incidents of sexual assault and harassment often provoke little outrage or response.

Ms Linda Wong, the organisation's executive director, said she hoped Lui's revelation would serve as a turning point in Hong Kong, where she said a victim-blaming culture was widespread.

"This is a new precedent - for Hong Kong people, especially victims of sexual violence, to break the silence," Ms Wong told AFP.

Lui said on Facebook that while she had not heard of other cases of sexual abuse in Hong Kong's sporting world, she believed there must have been incidents, and encouraged survivors to seek help.

"In Chinese culture, sex-related topics have always been seen as embarrassing, shameful or not to be publicly discussed," said Lui.