"Officers from Wollongong Police District charged a 27-year-old man in relation to an alleged incident involving a 19-year-old woman at a home unit in Wollongong about 1.30am Sunday 9 December 2018.
"The man, from Coniston, was arrested when he attended Wollongong Police Station about 3:40pm today (Thursday 13 December 2018).
"He has now been charged with one count of aggravated sexual assault in company.
"Bail is now being determined.
"Inquiries are continuing."
The incident had been reported to the NRL Integrity Unit by the Dragons earlier in the week, according to Fox Sports.
De Belin was reportedly at a Wollongong nightclub in the early hours of Sunday with a group of people, which included the woman and a fellow rugby league player, according to the Daily Telegraph.
De Belin, 27, made his NRL debut for the Dragons in 2011 and has played a total of 154 games to date.
He made his State of Origin debut in 2018 where he featured in all three games of the Blues' series win.
De Belin has denied the allegations and any wrongdoing.