Accused nightclub rapist Luke Lazarus described as "a nice guy" in court.

A former promoter of a Sydney nightclub has described a man who allegedly raped a young woman as someone she would turn to for help if she felt uneasy around another man, a judge has been told.

“He was someone we would go to if we were feeling uncomfortable with another guy to save us,” the woman who cannot be named said in the NSW District Court on Wednesday.

Luke Andrew Lazarus, who is facing a judge-alone retrial after an earlier conviction was quashed on appeal, has pleaded not guilty to having non-consensual anal sex with a woman in May 2013.

The 25-year-old allegedly told the woman, then 18 and on her first night out in Kings Cross, that he was the part-owner of Soho nightclub and offered to introduce her to the DJ in the VIP area.

His father Andrew Lazarus was an owner of the nightclub at the time.

Luke Lazarus is alleged to have raped the woman in a laneway behind the nightclub.

When asked during cross-examination about her reaction to the "serious allegations", the former Soho promoter said: "I was very shocked as was anyone else who found out about it as well".

"He was a nice guy, we all thought that as well."

A friend of the complainant, giving evidence earlier on Wednesday, said she was talking to someone on Soho's dance floor and when she turned around her friend "was no longer there".

She left the nightclub and tried to contact her friend to see where she was but she did not receive an immediate reply.

She eventually found her friend on the street and said "she was just a mess".

"She was hunched over, she couldn't really stand and she was very upset," she said.

The woman's older sister also testified on Wednesday saying her sister was "quiet" and "reserved" the following day adding "there was no real emotion in her voice".

When asked by crown prosecutor Cate Dodds whether the quiet behaviour was normal, the 31-year-old sister replied: "no, definitely not".

The older sister took her younger sister to Chatswood police station to report the 2013 incident before she underwent a sexual assault examination at Royal North Shore Hospital.

The trial is continuing.

If this post brings up any issues for you, or if you just feel like you need to speak to someone, please call 1800 RESPECT (1800 737 732) – the national sexual assault, domestic and family violence counselling service. It doesn’t matter where you live, they will take your call and, if need be, refer you to a service closer to home.

Feature image: Nine News