After questioning by detectives from the sex crimes squad, Hayne was charged with aggravated sexual assault — inflicting actual bodily harm.
The charge carries a maximum 20-year jail term if Hayne is convicted. The NSW Criminal Code states for "circumstances of aggravation" means circumstances in which "the alleged offender intentionally or recklessly inflicts actual bodily harm on the alleged victim".
It's understood the alleged victim was interviewed by the NRL's integrity unit before the matter was referred to police.
A spokeswoman for NSW Police told news.com.au: "Police are investigating following reports a woman was sexually assaulted by a 30-year-old man in late September.
"The investigation is being led by detectives from the Child Abuse and Sex Crimes Squad."
The claim likely comes as no help to Hayne's pursuit of a new NRL contract, after his most recent deal with Parramatta expired on October 31. The Eels had been hopeful at least one other player could be picked up by another club to fit Hayne into next year's salary cap.
"As this is a police matter the club will be making no public comment in relation to these reports," a Parramatta spokeswoman said.