Jarryd Hayne has been arrested after handing himself in to Sydney police.
The incident allegedly took place on September 30, the night of the NRL Grand Final, which Parramatta's crosstown rival, the Sydney Roosters, won.
Australian media's Nine Network reported the alleged victim had been in touch with Hayne via social media and that he travelled to a house in the Newcastle region of New South Wales and had a sexual encounter.
Hayne went to Ryde Police Station on Monday afternoon to speak with detectives from the NSW Sex Crimes squad.
Police declined to charge Hayne after investigating the allegations but the woman lodged a civil suit.More news: Samsung Galaxy S10 LEAKED patent shows notchless and unique design
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This would mark the second time Hayne has been accused of a sex crime, having been accused back in 2015, when a woman in the United States of America claimed he raped her after she had been drinking and passed out.
Jarryd Hayne is a professional rugby league footballer who most recently played for the Parramatta Eels in the NRL.
The former Parramatta and NSW origin star is now out of contract and the allegations will severely damage his prospects of a new NRL deal.
News of the alleged sexual assault broke last week, when it was revealed a complaint had been made to the NRL Integrity Unit.
Hayne spent the night in jail and was charged with aggravated sexual assault-inflicting actual bodily harm after questioning from detectives in the sex crimes squad.