Australia is facing what is being called a 'hostility epidemic' as more and more customers take their frustrations out on innocent shop assistants, simply trying to do their jobs.

From punches being thrown to workers being crash tackled to the ground and tens of thousands of dollars in damage being done to stores - shoppers are quickly becoming so enraged they are finding themselves before the courts.

Nathan McDonald is a fourth-degree Black Belt but is also a Brisbane-based business coach whose corporate clients have enlisted his martial arts expertise to train employees in what to do when things turn violent.

Australian workers are being terrorised while in the workplace due to a 'hostility epidemic' sparked by angry customers. (A Current Affair)

"It's getting worse and worse and you can see a lot more happening, a lot more verbal and a lot more physical aggression really happening out there," Mr McDonald told A Current Affair .

"I think society today is expecting things to be done immediately, add that to alcohol, drugs and low tolerance and you've just got a melting pot of aggression out there," he said.

He's developed a series of courses that specifically deal with, diffuse and offer self-defence solutions when facing an aggressive situation in the workplace.

From punches being thrown to workers tackled and abused, shoppers are becoming so enraged they find themselves before the courts. (A Current Affair)

A spike in the number of incidents of consumers targeting vulnerable employees has resulted in self-defence courses being developed for workers. (A Current Affair)

The workshops are now being delivered right across Australia. He says awareness in the workplace is key.

"Normally you can tell someone is getting angry and you can see it escalating," Mr McDonald said.

"It's about learning how to deal with that by agreeing with the person and letting them know that you understand that there is a challenge and you do want to try and help, and try and de-escalate the situation as quickly as possible."

Black Belt martial arts coach Nathan McDonald trains employees in what to do if a workplace turns violent. (A Current Affair)

Mr McDonald's courses train people how to diffuse a situation before they turn too violent. (A Current Affair)

Dr Gary Mortimer, a retail expert based at the Queensland University of Technology, says these days it doesn't take much to tip customers over the edge.

"What we are finding is consumers are just time poor, we are busy, we get frustrated very easily, a lot of stuff happens before we even get to the shopping centre," he said.

A recent survey of 6000 retail and fast food workers found 85 percent of them had experienced verbal abuse from customers and 14 percent had suffered physical violence, prompting their union to launch a national campaign with the message "No One Deserves a Serve".