Premier Dr Denis Napthine has indicated that the upcoming May state budget will outline how his government intends to implement the link from Southern Cross Station to Melbourne Airport.

The airport is currently only served by road transport and caters for 30 million passengers a year, although this number expected to double over the next 20 years.

Napthine says the government is undertaking detailed design, planning and consultation work on the new link, which will use the existing electrified suburban network from Southern Cross Station as a far as Albion on the Sunbury line. From here a new link will be built with a connection to the Jacana freight corridor, terminating at a new elevated station at Melbourne Airport.

Services will run every 10 minutes during peak hours with a journey time of around 25 minutes while metropolitan and regional commuters will also be able to access the airport at via the key interchanges of Footscray and Sunshine.

The government has not released cost estimates, but speculation in the local media has put the figure at around $A 3bn ($US 2.8bn).