The Victorian government has released its business case for an above-ground Melbourne Airport train station and a new station at Keilor East as part of the airport rail link project.
Transport Minister Jacinta Allan said an elevated airport station would cause less disruption in the construction stage, be quicker to build, and save up to $1 billion.
"Cities around the world have a rail line to their airport, and now Victoria will have one too," she said.
A new train station will also be constructed as part of the project at Keilor East, which Ms Allan said would connect 150,000 people in the area to the rail network.
"It's going to connect them to Victoria's rail network for the first time," she said.
The rail link is designed to allow passengers to travel between the airport and the CBD through Melbourne's western suburbs, with trains to run every 10 minutes.
The journey between the airport and CBD is expected to take half an hour.
The federal and state governments have each committed $5 billion to the project, which is slated to be completed by 2029.
Ms Allan said the business case released on Wednesday is consistent with the $8 to $13 billion the Victorian government previously estimated.
She said the rail link will connect to the metro tunnel, scheduled to be completed by 2025, and 30 existing stations would have a "direct connection to Melbourne Airport".
"The rest of the network will be serviced by just having about one interchange," she said.
Ms Allan said the project will provide 8,000 jobs for Victorians during the construction phase.
She said ticket prices had not yet been decided, with the business case using figures from Sydney's airport link fares.
The business case estimated the project's benefit-cost ratio is up to $2.10 for every dollar spent.
The Sky Bus service, which takes passengers between the airport and Southern Cross station, is expected to continue operating after the rail link is completed.
Melbourne Airport's chief of ground transport, Jai McDermott, said the airport supported a rail link, but it would prefer an underground station.
"Melbourne Airport's preference has been, and remains an underground station, which provides a superior passenger experience, safeguards for future connectivity and is appropriate for Victoria's international gateway," he said.
"It is important that the new rail station works for all airport users, not just those who arrive by train, and that it is a station all Victorians can all be proud of.
"We continue to work in good faith with the Victorian government to deliver this important project for Melbourne, however we are yet to agree on station location and design."
Ms Allan said both state and federal governments supported the above-ground station.
An auditor-general's review released Wednesday found the government's business case was delivered "too late to inform key government decisions on the project".
It also found the government's consideration of alternative options was "not sufficiently comprehensive to provide confidence to decision-makers that the right investment option was recommended and selected".
The government rejected the audit's findings, which were also critical of the Suburban Rail Loop project.
"There was a vigorous and rigorous process that is worked through for all of our projects," Ms Allan said.
"In the case of the Suburban Rail Loop and the airport rail project, they are big multi-year projects that did require an approach that was appropriate for that size and scale.
