A man was left lying barely conscious on train tracks at Flinders Street Station when an argument over a cigarette turned nasty.

The alleged victim, known only as Gary, has told Seven News he feared what would have happened had commuters not rushed to help him just moments before a train was due to arrive.

CCTV footage of the incident shows the 54-year-old standing on a platform and arguing with a younger man during the evening peak hour.

A women and another man join the argument before a hefty shove sends Gary flying head-first onto the tracks.