Melbourne is the only airport among the world's 50 busiest without a rail link or one on the way, other than five heavily car-dependent American cities.

A new analysis is to be released by the Public Transport Users Association as part of an event they are staging on Friday. It shows Melbourne – with 28 million passengers passing through it each year – is the only Australian airport in the top 100 without a rail link.

The other top 50 cities without an airport rail link are Las Vegas, Houston, Charlotte, Orlando and Detroit.

Athens has just over half the number of passengers as Melbourne but has a rail link; Oslo with a population of more than 600,000 and Salt Lake City with just under 200,000 residents have rail links. Melbourne's population is 4.4 million.

About 12,500 workers travel to the Melbourne airport each day and, contrary to widespread belief, the Citylink contracts do not prevent construction of a heavy passenger rail link to the airport.