Vicious attack filmed at Perth festival

Sickening footage of a young man kicking a security officer in the head at a Perth music festival has emerged on social media.

The security guard, who was trying to restrain a man, collapsed after being kicked before being helped by distressed onlookers.

West Australian Police said they were investigating the incident, which was filmed at the under 18 Perth Goodlife music festival on Saturday.

Scores of people condemned the "gutless" act on Facebook, posting comments to the video that has been viewed more than 100,000 times since it was uploaded on Sunday evening.

"This is sickening", one Facebook user wrote, while others described the young man who kicked the guard as a coward and low-life.

"No matter what the sitch (sic) you don't just boot a bloke in the head while he's down let alone doing his job," another man commented.

A security guard also weighed in to the online debate, saying he often feared for his safety when working at music festivals and clubs.

"I understand too well about this and I was always worried that I would never go home," he said.