Zhe Ji, 30, was convicted in his absence and a warrant issued for his arrest after he failed to turn up to Wollongong Local Court on Tuesday.

The Pagewood resident originally pleaded not guilty to two charges of wilful and obscene exposure in public space and two counts of carrying out a sexual act with another without consent.

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Documents tendered to court said two woman were sitting on Woonona Beach on January 3 after going for a walk with their dog at about 8pm.

Upon sitting just south of Woonona Surf Club on a blanket they saw a man, who police allege is Ji, walk from the water towards them before the dog started barking at him.

The friends described Ji as a man aged between 25 to 30 years old, thin build, black bowl-style hair cut, wearing a blue jacket, track suit pants and dark coloured runners.

Police allege Ji walked a short distance away before turning to face the women as he put his hand in his tracksuit pants and pulled them down to expose his genitals before masturbating.

Police allege he did this for up to 10 seconds directly in clear view of the woman, who were "horrified" with what was happening, the documents said.

Ji then allegedly walked away and up the track before continuing through the car park of Nicholson Park and onto Woonona Railway Station.

The woman reported being "quite traumatised" and called Triple 0.

Police arrived at the train station and found Ji, who was wearing the same clothes the woman described.

When questioned by police, Ji allegedly denied he had been on the beach and that he approached two women.

Upon further questioning, Ji allegedly admitted he was on the beach taking photos with his phone, which officers seized and found two videos taken a short time before.

Police arrested Ji and he was taken to the Wollongong Police Station.

Ji could not tell police where he lived or provide contact details. Officers contacted border officials who confirmed he was in Australia on a student visa.

Officers established he was a student at the University of Sydney but could not contact the Chinese Embassy to inform them Ji had been arrested and charged.

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