An Australian woman has been charged with raping another woman in the ladies toilet of Brisbane's Caxton Hotel.

Anne-Marie O'Loughlin, 25, is said to have kissed the other woman at the nightclub in the early hours of November 29 last year when she went alone to the bathroom, the Brisbane Times reported.

Opening the Crown case, prosecutor Chris Minnery told the jury the victim, who cannot be named and who was at the hotel with her partner and friends, returned the kiss in an effort to get away.

But O'Loughlin pushed her head into a wall and inside a toilet cubicle attempted to put her hand down her pants.

Minnery said O'Loughlin then scratched the woman's breast in the process of pulling her top and bra away before digitally raping her twice.

He said the alleged victim banged on the cubicle wall to get the attention of someone in a neighbouring stall, who announced she was getting security.

O'Loughlin left the toilet, but forgot her purse containing her identification in the cubicle, and was later detained outside the hotel.

She told police she had kissed the woman and that nothing else had happened between them, but she was charged after skin samples found under her fingernails matched the victim's DNA.

O'Loughlin pleaded not guilty to two counts of rape, deprivation of liberty and sexual assault at the Brisbane District Court.