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.

While many argue an airport rail link is desperately needed for Melbourne, others – including American public transit expert Jarrett Walker – have said Melbourne Airport has the best public transport of any Australian airport, including Sydney and Brisbane with their rail links.

SkyBus is a privately run service to the airport that charges $18 for a one-way trip and departs every 10 minutes between 5.30am and midnight. It has no dedicated bus lane, and its services often are slowed by traffic.

The Public Transport Users Association argues so many other governments around the world have built rail lines to their airports because there was a recognition rail was the most efficient transport mode.

"Only mass transit can ensure that large numbers of people – both passengers and workers – can reach the airport quickly and efficiently," an association spokesman, Daniel Bowen, said.

Of the world's 100 busiest airports, 64 have rail services. Toronto and Helsinki both opened their rail lines in June this year.

Helsinki airport's new rail line opened in June.

Another six have dedicated shuttle buses connecting to nearby rail lines, and a further 17 have rail connections under construction.

Toronto airport also this year added a new rail line.

In 1963, the Bolte government first considered a proposal for a fast rail service to link Tullamarine with the city. And as one of the first international airports planned with a rail link, Tullamarine was ahead of its time.

But since the airport opened in 1970 none of the promises to build the rail link have been fulfilled.

While the Napthine government pledged construction of an airport rail link going into the 2014 state election, full funding was not provided.

Labor has prioritised construction of its $11 billion Melbourne Metro project.

Public Transport Minister Jacinta Allan said a rail line to the airport was "a worthy long-term project".

"But our priority is delivering on the major public transport projects we promised, like Melbourne Metro rail and the removal of 50 dangerous and congested level crossings," she said.

But Mr Bowen said because planning for the Melbourne Metro tunnelling was well advanced, it was time to get on with devising the airport link, "so that we don't wait another generation for it to happen".

The airport – which earns $345,000 a day from parking charges – last week increased its parking prices.

The cost of parking for between 15 and 30 minutes at the airport increased from $6 to $10. And it now costs $29 to park at the terminal for between one and two hours – up from $24.