

More than $1 million a day will be spent on average for the next four years to plan a new rail tunnel beneath the CBD, before construction even begins.

Premier Daniel Andrews on Tuesday said there would be $1.5 billion in funding in next week's budget for the Melbourne Metro project. Construction will start in 2018.

Hundreds of millions of dollars will be spent planning and designing the rail tunnel. At least half a billion will also go on property acquisition, and more will be spent moving services such as gas, water and transport infrastructure to make way for the project.