SEOUL • South Korea's double Olympic short-track gold medallist Shim Suk-hee has accused her former coach - already convicted and jailed for repeatedly beating her over many years - of sexual assault, her lawyer said yesterday.

Shim filed her complaint against Cho Jae-beom to police last month, on the same day she testified at his appeal against a 10-month jail sentence for physically assaulting her.

The 21-year-old has four Winter Olympic medals to her name, including relay golds at both Sochi 2014 and on home ice at last year's Pyeongchang Games.

Shim told police that her coach sexually violated her from the age of 17 until last January, a month before the Olympics, her lawyer said.

"This is a grave crime that our society should not overlook," Im Sang-hyeok told AFP.

Some of the incidents took place at government-managed sports training centres, he added, demonstrating how vulnerable athletes can be to loopholes in the state management system.

Coaches in the country hold immense sway over athletes' careers, and physical and verbal abuse are known to be rife.

In addition, South Korea remains socially conservative and female sex crime victims can face public shaming.

Shim "kept it all to herself" until recently, Im said of the sexual assault allegations, "in fear of the potential stigma she could face as a woman and impact on her family as well as reprisals by Cho".

She "mustered up the courage" to reveal the case in hope of preventing other athletes from suffering similar fates, he added.

In response to Shim's accusations, South Korean authorities yesterday promised to strengthen penalties for sexual offenders.

Lifetime sport bans - currently applied to offenders convicted of rape or sexual assault - will be extended to those who commit sexual harassment, said its deputy sports minister Roh Tae-kang.

Cho has denied the sexual assault accusation, according to South Korean broadcaster SBS.

A ruling in the physical assault appeal is expected on Jan 14.

AGENCE FRANCE-PRESSE