A $3 billion high-speed underground rail line connecting Sydney’s CBD to Parramatta is set to be the centrepiece of the NSW government budget.

The budget, to be handed down on Tuesday, will also earmark $28 million to finalise the final business case for the project expected to begin in 2020, The Daily Telegraph reports.

“This is a super train for three million people in Western Sydney,” Transport Minister Andrew Constance said.

“It will absolutely smash the travel time between Parramatta and the Sydney CBD via Olympic Park to less than 20 minutes.”

The construction of the so-called Metro West project has a preliminary completion date of around 2025.