Metro wants to build multi-storey car parks at some of Melbourne's busiest railway stations, and potentially charge commuters to park there.

A series of prefabricated multi-deck station car parks would encourage more people to take the train to work instead of driving, and increase public transport revenue, Melbourne's rail operator argues.

A multi-level car park is being built next to Syndal station on the Glen Waverley line. Credit:Simon O'Dwyer

Parking shortages at suburban stations discourage too many people from using public transport, Metro says, and opportunities to expand parking at ground level are rare and often prohibitively expensive.

"Many inner city stations have limited land available and acquiring more for further expansion 'at grade' is expensive and likely to meet with community resistance," Metro advised the government in a leaked five-year plan from 2013.