A high-speed rail line between Sydney and Melbourne could be finished in just over 20 years, allowing travel between the two cities in less than three hours, according to a multimillion-dollar study commissioned by the federal government.

But the rail line would cost about $50 billion and require long tunnels into the heart of Sydney, says the study, to be released on Thursday by the Federal Transport Minister, Anthony Albanese.

The study, which looked into the prospects for an east coast high-speed rail network linking Brisbane, Newcastle, Sydney, Canberra and Melbourne, says the first part of the line to be built should be between Sydney and Canberra.

If construction and planning approval were accelerated, this line could be running by 2030, allowing passengers to travel between the two cities in 64 minutes. Extending high-speed rail to Melbourne would take another five years and push the cost of the line to $50 billion. If it was ever extended north to Brisbane the cost of the project would rise to $114 billion.

Invitation to respond to the report: Federal Minister for Infrastructure and Transport Anthony Albanese. Credit:Mick Tsikas

In a release, Mr Albanese said he would start public consultation on the high-speed rail report on Thursday, and would invite responses to the report until the end of June.