A Queensland law expert says Madonna has committed an act of sexual assault if the fan she exposed to the world did not consent.
The queen of pop is under fire for pulling down the top of a female fan she had invited onto the stage in Brisbane on Thursday night. The woman in question was not wearing a bra.
University of Queensland law expert Dr Paul Harper says on face value, pulling down a woman's top in public to expose their breast is an act of sexual assault, if it's non-consensual.
The TC Beirne School of Law lecturer said the person who has been violated must make a complaint for police to act.
"The woman is going to have to put a complaint in," Dr Harper told AAP.
"The issue is, has the girl consented? By going up on stage you consent to some physical contact... you don't expect to be exposed at a Madonna concert.
"If the woman doesn't consent then it's sexual assault. It essentially carries jail time, but even if they press charges the lady, realistically, may suddenly consent.
"The police aren't going to do anything about it unless she complains because she is an adult and also you don't know what was said on stage. You'd assume not all the discourse would be between Madonna and the girl. The security people may have said something was going to happen and do you mind."
The latest stunt by Madonna has not gone down well.
UK commentator Piers Morgan has called on the Material Girl to cancel her tour because she's having a "meltdown".
Madonna was some two-and-a-half hours late on stage on Wednesday for her first Brisbane concert, while being four hours late on stage for a Melbourne show last week.
The video of Madonna pulling down the woman's top has gone viral and Morgan tweeted on Friday, "Madonna is in total meltdown. She needs to cancel this tour asap."
Judging by Madonna's comments on stage on Thursday, she knew was treading close to the line or even crossing it when she exposed the woman's breast at the Brisbane's Entertainment Centre in front of thousands of fans.
"She is the kind of girl you just want to slap on the ass and pull oh s***," Madonna is heard saying in a video which has gone viral.
"Sorry, sexual harassment. You can do the same to me," Madonna says after pulling down the top.
Commentators have tried to rationalise Madonna's diva behaviour by saying she is going through a tough custody battle with her ex-husband Guy Ritchie over their 15-year-old son Rocco.
There are just two tour dates remaining on the star's Rebel Heart world tour, which kicked off in September in North America and ends on Sunday at Sydney's Allphones Arena.
Her last two concerts, on Saturday and Sunday, will also be filmed for a DVD.