Gang's crime rampage captured on camera

Shocking vision has emerged of a notorious teen gang terrorising Melburnians in a crime spree that knows no boundaries in terms of suburbs or violence.

Security video, obtained exclusively by 7News, shows how an unsuspecting victim was randomly attacked by a member of the KYR gang, otherwise known as Kill Your Rivals, at Keilor Plains train station.

The 17-year-old unleashed a relentless assault on the young Sri-Lankan man who had been in the country for less than two weeks and had been visiting a friend.

The footage shows the gang member as he approached his victim before throwing him to the ground and repeatedly punching him.

No less than 30 punches were delivered during the beating which lasted just over a minute.

At one stage, an onlooker attempts to intervene, but then backs off.

The culprit then fled the scene, while others on the platform rushed to help the stricken man, who miraculously escaped major injury.

His attacker was caught and jailed for two months.

In another incident, three teenage gang members wielding an axe and a baseball bat terrorised staff at a McDonalds outlet in Melbourne's north-west.

They hid their faces, but their menacing behaviour is all too familiar to police and their growing number of victims.

After threatening staff, including a young woman, they grabbed cash from the store office before taking off on foot.

The gang is believed to be responsible for at least 40 armed robberies in the Brimbank area, but is suspected of carrying out 14 more in suburbs, including Box Hill, Mount Waverley, Notting Hill and Brooklyn over the past fortnight.

Police have told 7News the majority of gang members are migrants of Maori or Islander background. Some have older relatives in jail or connections to gangs in New Zealand.

The gang members are aged between 14 and 18.

Police fear as they get older their crimes will become even more serious.

Anyone with information about these incidents is urged to call Crime Stoppers on 1800 333 000.