Two teenage girls have been charged with assault after a confrontation with ticket inspectors in which one girl was picked up and slammed into the ground after hitting an officer in the face.

Closed-circuit footage of the incident, at Flinders Street Station on July 31, shows the girl bypassing the myki barriers and walking through an open gate, then being grabbed by the clothing by a Metro authorised officer.

The girl turns and hits the man in the face. He then picks her up and slams her into the ground in a move similar to an illegal rugby spear tackle.

The footage was obtained by state Greens leader Greg Barber, who said it revealed ''brutal and unnecessary treatment by a private company, Metro, against people it calls its 'customers'''.