SARAH FERGUSON, PRESENTER: A spate of random attacks has prompted governments around Australia to take action against alcohol-fuelled violence. It's also provoked a surge of interest in self-defence, causing amateur combat classes to spring up around Australia.

One that's attracting scores of followers is a controversial self-defence method pioneered by the Israeli Army which teaches tactics like eye gouges and throat strikes designed to inflict maximum physical harm. Its proponents argue it's the perfect weapon for dealing with drunken thugs. But criminal lawyers are warning it could land its practitioners in jail.

Conor Duffy reports.

CONOR DUFFY, REPORTER: These young professionals have a new way of winding down in the evening. Most have walked from their office jobs in the inner-city, straight into a knife fight.

It's part of a boom in self-defence as Australians try to arm themselves against unprovoked attack. Here they practise Krav Maga, Hebrew for "contact combat". If it looks like they're preparing for war, there's a good reason. Krav Maga was designed in the 1930s to protect European Jews from fascist attacks. Later it became mandatory in the Israeli Army.

ALEX TRAFTON, KRAV MAGA DEFENCE INSTITUTE: We're training civilians to protect themselves from common forms of violence and whether that knowledge was gleaned in 1930s Europe, anti-Semitic riots in Europe, whether it was gleaned from conflicts in the Middle East, it's irrelevant to me. I mean, if the techniques are effective and they're legal and they work, then I'm comfortable using them and I'm comfortable teaching them.

CONOR DUFFY: Head instructor Alex Trafton worked as an Israeli military contractor.

A few years ago, Krav Maga was unheard of here. Now new schools are opening right around the country.

ALEX TRAFTON: It can look brutal. It certainly can. But if you look at what the need for Krav Maga is, it's these king hits in Kings Cross. There's a 17 or 18-year-old kid who's now dead because of this. Asked him if he would've liked to be able to punch the guy in the throat first or be able to kick him in the groin first. And I think at this point - I mean, the options are clear.

CONOR DUFFY: Krav Maga doesn't just teach people to go for the throat, but also the eyes, neck and groin and to hit them hard.

ALEX TRAFTON: You need to target vulnerable areas, be very aggressive in your counter-attack to disable that person - that that is the fundamental principle of Krav Maga.

CONOR DUFFY: Online videos for Krav Maga also teach how to break bones.

(YouTube video of Krav Maga shown)

Another video shows the best way to attack the eyes.

KRAV MAGA INSTRUCTOR (YouTube video): And eye strikes. You want to make sure that when you stick your finger, they're not limp. You have to tighten 'em up, make 'em firm and hard.

CONOR DUFFY: Criminal lawyer Andrew Tiedt says that technique could land Krav Maga students in jail.

ANDREW TIEDT, CRIMINAL LAWYER: In the majority of cases, I'd say eye gouging probably goes beyond what a court would see as being appropriate in those circumstances.

CONOR DUFFY: If you did blind someone, how severe could the legal ramifications be for you?

ANDREW TIEDT: You'd go to jail, definitely.

CONOR DUFFY: By day, Blair Beven is an intellectual property lawyer. In the evenings, he turns into a warrior. A random attack in a pub left him with good reasons to want to defend himself.

BLAIR BEVEN, LAWYER: He picked up a glass and he smashed that into the side of my face. So, it was a pretty violent act, completely unexpected and unprovoked. I was very lucky. I could've lost an eye.

CONOR DUFFY: Blair Beven recently used these moves to deflect an attempted kinghit while watching a rugby game.

BLAIR BEVEN: This guy came at me pretty aggressively. And I was able to block his punch and then was able to strike him in the face, which is not nice, but I felt pretty threatened and that was the end of it.

CONOR DUFFY: But defence can easily turn into attack. Krav Maga Sydney posted this YouTube clip on its Facebook page for students, calling it a great video illustrating striking against two people.

ANDREW TIEDT: It seems like an incredible assault.

CONOR DUFFY: So it'd be dangerous for people to view that as legitimate self-defence?

ANDREW TIEDT: To say the least.

CONOR DUFFY: For students flocking to fighting schools, the cautionary message is that some of the more aggressive techniques have a danger of their own.

ANDREW TIEDT: I think people should be very careful if they plan on defending themselves aggressively, that they do only what is reasonable to defend themselves from the fear they perceive. If people are going to go out there and start flogging anyone who looks at them sideways, they'd be taking a very, very big risk.

ALEX TRAFTON: It's important that I reinforce that they do it always legally and that the force is proportionate. OK. Also that I will not train people who have a violent history, who have violent tendencies due to mental illness or have a criminal record. I won't at all be involved in training those people because it's not - this is a tool for people to protect themselves, not to victimise people.

CONOR DUFFY: Former Army commando Kevin Marshall runs a Krav Maga program called Fight Like A Girl.

KEVIN MARSHALL, FIGHT LIKE A GIRL: We have young mums, women, people that didn't feel comfortable, people that have been attacked in the past, also members of the lesbian, gay and transgender community who didn't feel comfortable training. And I saw that they needed this training so I came up with the concept of Fight Like A Girl and developed a program and the rest is history.

CATHY GRAPSIAS, FIGHT LIKE A GIRL: We've had people come through very, very quiet and very meek and mild and turn into lionesses after that, so it's great to see.

CONOR DUFFY: Kevin Marshall and instructor Cathy Grapsias also teach Krav Maga to prostitutes and strippers, acting out a range of attack scenarios.

KEVIN MARSHALL: That's a very misaligned and marginalised group in the society and the people that really need self-defence skills. Those women are in high-risk occupations and they are sometimes really in the real risk of danger. I remember when I initially spoke to the people from SWOP - Sex Workers Outreach Program - the president had to cancel our meeting because one of her workers was killed the night before.

CONOR DUFFY: And back at the Krav Maga school, Alex Trafton realises the power that comes with violent skills and is also tailoring his program.

ALEX TRAFTON: I certainly wouldn't intentionally inflict lasting harm on someone, but if that was the result of their choice to try and kill me or seriously injure me, then I would be able to live with that.

SARAH FERGUSON: Conor Duffy with that report.