A woman enjoying a night out with friends at a Spiderbait gig says the last thing she expected was to be urinated on by a man and have others around her act like it was no big deal.

Melbourne woman, Belle Nolan, 33, went to a Spiderbait gig in the Melbourne CBD in February with friends.

She says at around 10.40pm, at the venue, 170 Russell, she felt liquid on her leg as she watched the band play.

She told Fairfax Media at first she thought someone had spilt their drink.

But when she looked down she realised the ‘liquid’ was warm, as her friends yelled at the man she says his reaction shocked her.

“I was horrified and kind of in shock,” she told The Daily Mail.

Belle Nolan, with a friend. Image via GoFundMe.

The side-spray even hit a woman standing next to her, whose daughter screamed at the man.

“People around me were yelling at him, and he looked right at me and kind of shrugged and smirked like it wasn't a big deal.”

But Ms Nolan says the man needs to be held accountable for his actions.

"It was weird, it was as though it was kind of like a bit of a minor inconvenience, as though it was normalised or something," she said.

"People thought it was bad, but they kept watching the gig."

Police have released this image of the man. Via Facebook.

Her friend caught the attention of a security guard who was informed and threw the man from the venue. But to Ms Nolan’s surprise even the security guard did not think to take down his details or call police.

Ms Nolan said she was "shocked.”

Spiderbait say they are horrified. Via Facebook.

Her story mirrors that of a Canberra mother who claimed earlier this year that she was urinated on during the ‘Groovin the Moo’ music festival in Canberra.

Joana Perkins told the ABC she attended event to keep an eye on her 15-year-old son Sam and her nine-year-old daughter Ema.

"We were enjoying ourselves when I noticed a man come up behind me and I thought I sensed something that he was fiddling with his penis and unfortunately I started feeling urine running down my leg," Ms Perkins said.

"I turned around and he had his penis out and was weeing on me, at which point I grabbed him by the arm and said 'you're coming with me' and moved him away from where we were."

Ms Perkins said when she was eventually approached by security.

"Two guards came over and asked me what happened and I said 'this guy's just peed on me' and you could see the pee marks and they took the guy away," she said.

"Now obviously I had wee down my leg and a crying nine-year-old and I wasn't going to hang around so I headed out to the exit with my son and carrying my daughter.

"I wasn't heading out to check on what the security guards were doing, but what I noticed is that they were laughing, patted the guy [who] was absolutely over-the-top inebriated or high and let him go off on his merry way."

Ms Nolan, pictured with friends, says the incident left her feeling humiliated. Via Facebook.

Both women have expressed dismay at how the act was ‘laughed off.’

"I do think it happens more than is reported, even just talking about my story, other people have said, 'oh that happened to me as well'." Ms Nolan told Fairfax Media.

She reported the incident to police – an act she says raised eyebrows among those she told who were surprised she considered it a crime.

"I take it very seriously when someone whips out their penis in a public place and urinates on me," she said.

"It's not seen to be a crime, but it actually is."

Ms Nolan says the incident left her feeling humiliated.

"I can't really describe it. I know I haven't done anything wrong, but I felt really embarrassed about it."

"I had to go through the rest of the night until I got home with urine on my leg and on my shoes and then I had to throw my shoes out."

Spiderbait, unaware of what was taking place at the time have released a statement overnight expressing their shock.

“We are so appalled at this awful and disgusting behaviour and that our valued fan Belle has had to endure at one of our shows, how can this happen?

"We are dumbfounded!? PLEASE everyone read this story and look at the CCTV photo. Especially Melbourne folk. We would really like to find this offensive, urinating fuckstick. Does anyone out there know him? All information is helpful and we do not condone this behaviour."

"Belle, we applaud you standing up and taking action. This type of behaviour is absolutely not to be tolerated!!! We are going to stop at NOTHING to find this creep. “

Belle Nolan says the assault was symptomatic of attitudes towards women.

"We should be able to go out and enjoy a night with our friends without being groped, or harassed, or in this case, urinated on," she told Fairfax Media.

Spiderbait said "Belle, we applaud you standing up and taking action." Via Facebook.

Police have released an image of the man.

He is described as being Caucasian in appearance, between 25 and 30, and about 187 centimetres tall, with a medium build, dark eyes and short dark hair.

He was clean shaven and wearing a purple shirt and dark coloured pants.

Anyone with information is encouraged to contact CrimeStoppers on 1800 333 000.