A Chinese student was left hanging her head in shame after pleading guilty to having sex in a busy street.

The girl, known as Wu Xinyi, 18, is from mainland China and was caught canoodling with a man outside her university halls at Hong Kong Polytechnic University in Ho Man Tin in April, reported the People's Daily Online.

However, her partner, Yang Hao, 19, who is a student at Hong Kong Baptist University, denied the charges during a court hearing on Thursday.

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Oblivious: Wu Xinyi, 18 and Yang Hao, 19 were caught having sex on busy street near bus stop in Hong Kong

Denial: Although the female student has admitted to the crime her partner is still pleading not guilty

Kowloon City Court heard that in the early hours of April 1 Yang was spotted removing the girls pants before the pair began having sex at a bus stop outside the residential halls.

Three minutes into the act, a security guard noticed what was happening and demanded that the couple stop but to no avail.

After going to notify the police, he then saw the teenagers engage in oral sex.

Guilty: Wu only found out about the explicit video after she returned from holiday and saw it online

The court also heard that the pair were so engaged in their activity that they didn't notice passers-by and the man only realised a police officer had appeared when he tapped him on the shoulder.

However, as the policeman did not see anything he could not take any action and Yang was only arrested a day later after the video surfaced online.

And the past came back to haunt Wu a week later when she returned from vacation to see a graphic video of the event online and decided to hand herself in to police.

Regret: Wu was in her first year at the Polytechnic University, studying Global Supply Chain Management

Change of heart: Originally Wu pleaded not guilty but changed her mind just two hours later

Both students originally pleaded not guilty to outraging public decency on Thursday, reported Cankaoxiaoxi.com.

However, Wu, who previously had no criminal record, made a swift U-turn just two hours later when she admitted to the offence.

Wu was in her first year at Hong Kong Polytechnic University, where she studied Global Supply Chain Management but her lawyer has voiced concerns that she may have to stop her studies.