Breakthrough in brutal NSW cold case

Twenty years after a young woman was sexually assaulted, bashed and left for dead in a Sydney nightclub car park, a man is in custody charged with the attack.

A breakthrough last year in the cold case of the 19-year-old found battered and unconscious outside Parramatta Leagues Club led to the arrest of 44-year-old John Clayton Sims in South Australia on Monday.

Police allege Sims met his victim in the club's nightclub on a Friday night in March 1996, with the woman believing he knew her boyfriend.

Detective Inspector Mick Haddow says at some point in the night she went with him outside.

"After a short dispute between the two, we'll be alleging that this male viciously and horrifically assaulted the victim," he told reporters in Sydney on Thursday.

"She was found a number of hours later unconscious in the car park by local police and she had suffered significant head injuries."

The woman was in Westmead Hospital for weeks, undergoing treatment for a brain injury and surgery for multiple facial fractures.

No suspect was identified until advances in forensic technology made it possible last year.

The case was referred to NSW Police's sex crimes squad and officers swooped on Sims in Adelaide on Monday night.

He was extradited on four charges - maliciously inflicting grievous bodily harm with intent, aggravated sexual assault, inflicting actual bodily harm and doing so with intent to have sexual intercourse.

Det Insp Haddow said the victim was "very pleased" with the result.

"These injuries were very, very significant and like any injury, it takes a long time to heal - the physical scars but obviously the mental scars continue," he said.

"There is no question the forensic capability of this police force and all police forces now, compared to 1996, have changed significantly."

Sims did not appear when his charges were mentioned in Sydney's Central Local Court on Thursday and there was no application for bail.

The case is due to return to court in July.