The federal government is set to promise $5 billion for a Melbourne airport train line and is suggesting the Victorian government gets on board with a 50-50 funding split.
Prime Minister Malcolm Turnbull will announce the funding pledge on Thursday, News Corp Australia reports.
The funding could mean construction starts as early as 2020, with a route selected from a business case already underway.
Mr Turnbull has written to Premier Daniel Andrews suggesting the two governments put in equal funding for the project, possibly using $2 billion Victoria will get from selling it's share of the Snowy Hydro Scheme.
Mr Andrews said in 2016 airport rail wasn't a top priority.
But in the last budget the state government funded the current business case.