A free concert scheduled in Melbourne's Fed Square was cancelled at the last minute on Friday night, with organisers citing overcrowding.

Thousands had flocked to the CBD to catch a glimpse of rock band Amyl and the Sniffers, who are currently touring as the opening act on AC/DC's world tour.

But fans were left disappointed, with the show cancelled eight minutes before the Melbourne band was due to take the stage.

Punters arriving late to the free all-ages show were greeted with signs stating the venue was full, with fences erected around the square to control the crowd size.

Some late-comers were seen kicking and attempting to break through fences after the crowd had reached its capacity.

Organisers cited safety concerns when announcing the cancellation over the public announcement s

See Full Page