Shocking sexual assault allegations against Dragons star Jack de Belin have emerged during his court appearance today.

The 27-year-old pleaded not guilty to the charge of aggravated sexual assault of a 19-year-old woman in Wollongong last December.

After the hearing was adjourned until mid-April and as de Belin walked from court making no comment, police documents tendered at the hearing contained details of the allegations against him.

It is alleged de Belin repeatedly raped the victim inside his cousin’s apartment, while his friend and co-accused Callan Sinclair, 21, watched on.

At one stage, police will allege de Belin invited Sinclair to participate, saying "come on have a go" as the alleged victim lay on the bed, crying.

St. George Illawarra Dragons player Jack de Belin arrives at Wollongong Local Court in Wollongong. (AAP)

It is alleged the woman later underwent a rape test at hospital and was observed to have injuries to her legs, neck, lower abdomen and shoulder.

Earlier, de Belin's lawyer David Campbell applied to the court for a bail condition, that his client report to police every Monday and Friday, to be dropped.

Mr Campbell said the reporting duties would "make it almost impossible" for de Belin to play interstate matches once the NRL season kicks off next month.

But police opposed any changes, arguing there was a "temptation for de Belin to flee" because he faced serious charges and a lengthy custodial sentence if convicted.

St. George Illawarra Dragons junior player Callan Sinclair (centre) arrives at Wollongong Local Court in Wollongong. (AAP)

Magistrate Roger Clisdell ruled otherwise, scrapping the reporting condition and saying de Belin was a "well-known sportsman" and he was satisfied he was not a flight risk.

Today’s decision by the court to remove any reporting conditions should guarantee de Belin's selection for the Dragons when they play the Cowboys in Townsville in the first round of the 2019 competition.