Greens leader Christine Milne says Australia will lag behind the rest of the world if it fails to lock in plans for high speed rail linking the eastern state capitals.
The party secured a feasibility study for the $114 billion project as part of its support deal with the Labor government, but Senator Milne says she's afraid it will fall by the wayside once the election is over.
"We don't want to see this plan collapse," she told reporters on Tuesday.
"We don't want to see Liberal and Labor prefer to spend money on coal railways, or east-west tunnels.
"Rather, we want to see advancement in urban rail. We want to be able to say that Australia is joining the rest of the world."
The cost of the 1750km line linking Sydney, Melbourne, Canberra and Brisbane has been put at $114 billion.
However, Greens deputy leader Adam Bandt said Australia's strong credit rating meant it was in a good position to make an investment in the project in the next few years.
"We are proposing an upfront investment of $1.2 billion over the next four years," he said.
He said the project would improve transport between the cities and generate more than 200,000 jobs over its lifetime.
The Greens have proposed a fast-tracked project timetable which would include setting up a High Speed Rail Authority to oversee it, an environmental impact study (EIS), surveying of potential rail corridors and a detailed finance and investment layout.
The Parliamentary Budget Office has costed an EIS at $570 million and the Greens' fast-track proposal at $664 million over the forward estimates period.
