"Break rooms" are popping up around Australia, but their customers aren't necessarily who you think.

People pay as little as $35 to suit up in protective gear and destroy bottles, plates and white goods with a baseball bat.

Break rooms have been established in Melbourne, Perth, and the Sunshine Coast, while in Sydney, more than 75 per cent of the customer base is female.

"We thought it would be guys, [but it's] rarely happened," Smash Brothers co-founder Johnny Li says.

"It's mainly girls. They come in packs."

Bats ready to be used to smash things in the smash room ( ABC News: Maisie Cohen )

The service hasn't been specifically marketed to women, but the organisers have told The Signal the trend is unmistakable.

"They come here, they release stress, they go crazy," Mr Li says.

"They can do whatever they want, as long as they're safe.

"It's a playground for adults, that's all it is."

Johnny, one of the men behind Sydney's smash room ( ABC News: Maisie Cohen )

He says apart from being heavily skewed towards women, it is hard to say who will walk through the door.

"We've had teachers, lawyers, doctors, students, even family come together," Mr Li says.

He says some people are there for the novelty of the experience, but others treat is as a serious attempt to relieve their stress and anger.

"Some of them have been referred by doctors or psychologists to come," Mr Li says.

And he says often it seems to do the trick.

"After they smash, they come out and [say they] felt amazing," he says.

Anger still a taboo for women

Psychologists say violence and even anger are still more taboo for women, and that may explain why they are especially attracted to break rooms.

"We don't give women many opportunities to express anger or strong emotions in their daily lives," the Australian Psychological Society's Heather Gridley says.

"We think that we're a lot more liberated now than we were 30 or 100 years ago, but many of the dynamics are just the same, I find.

"Women get judged more for how they express [anger].

"You can only go so far, you've still got to be nice."

Used bottles lie in crates, ready to be used in the smash room ( ABC News: Maisie Cohen )

There are different sets of unwritten social rules for men and women when it comes to anger, according to Associate Professor Tom Denson from the University of New South Wales.

In particular, he points to the trope of the angry male boss.

"It's very acceptable for men in high-status positions to show anger, no-one really worries too much about that, but a woman to do the same is very taboo," he says.

Does it work?

Reporters Angela Lavoipierre and Stephen Smiley prepare to enter the break room. ( ABC News: Maisie Cohen )

It's no wonder people feel good once they leave the break room.

Apart from having done some exercise, Associate Professor Denson says there are plenty of studies that show how aggression can promote an immediate sense of wellbeing.

"We know from neuroimaging research that it activates a lot of regions in the brain, but it activates reward regions of the brain," he says.

But experts say the idea that catharsis is an effective remedy for anger is outdated.

"For most people, if you get angry and you don't do anything and you just wait 10 or 15 minutes, the anger goes away and everybody's fine," Associate Professor Denson says.

"So, there's really no truth to this Freudian idea that you need to blow off steam."

A4 sheet lays out the rules for the Smash Brothers smash room in Sydney ( ABC News: Maisie Cohen )

In fact, he says, studies show that "angry rumination" may even make matters worse.

But Associate Professor Denson believes break rooms are probably harmless, as long as people do not walk in with overly specific anger.

"If you're going down there to break a taboo and have a bit of fun, it's probably not all that big of a deal," he says.

"But if you're going down there and you're really angry and you're thinking about the person that you're angry at, it's really not a good idea."