Texan rapper Riff Raff's Australian tour has been cancelled after he was accused of raping a woman who attended one of his shows five years ago.

In a statement posted on Facebook on Thursday, Melbourne woman Eliza Stafford accused Riff Raff, whose real name is Horst Christian Simco, of drugging and raping her in 2013, after being asked to come backstage at a show.

Texan rapper Riff Raff's Australian tour has been cancelled in light of a rape allegation.

"In 2013 I was raped by a man whose stage name is Riff Raff," she wrote.

"I was offered a 60ml ‘party’ shot. I took the shot, it was syrup and I immediately asked what it was. Riff Raff and his support act told me that it was codeine and started laughing. I don’t remember anything from that point."