It is Melbourne's sixth-busiest railway station, used by 28,000 passengers a day, a figure that has almost trebled in just six years.

Yet despite that extraordinary surge in patronage, South Yarra station has been all but ignored for the past 17 years, documents show, even though authorities knew it was struggling to cope with the growing crowds.

Since 1999, the full extent of investment in upgrading South Yarra station has been a refurbishment of its toilets, the addition of stainless steel platform benches and a cordless microphone system for staff, a freedom-of-information request has revealed.

The "South Yarra ticket barrier project", an expansion of the station foyer to "improve passenger flow", was proposed in mid-2011, the documents show, but did not proceed despite a Metro recommendation to Public Transport Victoria that it be "fast-tracked".