The proposal, put forward by Spanish manufacturing company Talgo, could slash the rail travel time between the two cities from four hours to just two and a half.

In a letter to NSW Transport Minister Andrew Constance, Dr Leigh stressed the importance of improving rail links between Sydney and Canberra..

"As you are aware, the current train time from Sydney to Canberra takes around four hours - considerably longer than the time to drive," read the letter, obtained by Fairfax Media.

"Many in the Canberra community and along the train route have expressed to me their concern that this is disadvantaging those who would prefer to travel by train, and leading to additional congestion on the roads."

Executives from Talgo travelled to Canberra last week to discuss the project with Dr Leigh, the opposition spokesman for competition and productivity.

It is understood Talgo has also met representatives from territory, state and federal governments, who have expressed some interest in the project.

Talgo has offered to lend Australia one of its trains free to test the feasibility of the project.

Its trains would run on the existing tracks between the two cities with little to no modification needed to railway infrastructure.

"[Talgo] are confident that with their system, the journey time could be reduced from 4 hours to 2.5 hours," Dr Leigh wrote to Mr Constance.

"I wonder whether your government might consider this, and at least see what the Talgo train could do?"

The full proposal would cost less than $100 million and could be completed in 12 months or less, Talgo commercial director Guillermo Martinez told The Canberra Times.

The Indian government is running trials of Talgo trains between the cities of Mumbai and New Delhi, where they have shaved four hours off the typical journey time of 16 hours.

Talgo project manager Salvador Flores said the primary reason the trains travelled so fast was because they used a "tilting" system that allowed them to maintain speed on corners.

"Mainly it's the passive tilting system that allows the train to run faster. It's a difference in technology," he said.

Mr Martinez said it was too soon to tell exactly how quickly the units could travel on Australian tracks, although Talgo trains are capable of 200 km/h.

They would have a similar passenger capacity to the trains now running on the Sydney to Canberra line, Mr Martinez added.

Last Thursday ANU professor Clive Williams, who has no commercial interest in the initiative, organised a community meeting to discuss the proposal.

"We had about 100 people show up to the meeting, it went very well," he said.

"The attendance was a mix of people who were just interested in the proposal, and those who were ex-railway employees.

"There was a lot of support for it. Now it's just a matter of building up momentum."

The Canberra Times has contacted the NSW government for comment.