The novel project could have been Sydney's had the O'Farrell government been just a bit more expansive in its thinking.

Materials would be moved on overhead conveyor belts. 

This is the message from the former federal Liberal MP Ross Cameron, who for two years has been trying to drum up support for a $100 billion proposal to remake much of Sydney with finance, labour and prefabricated steel and concrete from China.

Mr Cameron, a former Macquarie banker, says he met high-ranking Beijing officials to work on the plan. He has canvassed it with federal and state MPs, including Opposition Leader Tony Abbott who, Mr Cameron says, found it ''clearly attractive''.

And he has met the state's top transport bureaucrat who, according to Mr Cameron, loves the idea. But the government has rejected the proposal and will proceed with the $13 billion WestConnex project that will require significant taxpayer funding.

Under Mr Cameron's plan, submitted to the government last September, a consortium known as Aspire Sydney would build the M4 East motorway in exchange for the rights to develop more than 150 hectares of state-owned land along the rail corridor from Central to Strathfield.

Rail lines would be rebuilt underground and the land filled with prefabricated high-rise apartments, commercial space and the M4 East. Construction materials would be moved to the site on overhead conveyor belts from a new port near Glebe.

Thousands of labourers, consultants and engineers would be brought from China and elsewhere. Mr Cameron said he had two meetings last year with transport director-general Les Wielinga to discuss the idea.

''He walked me over to the edge of his office. He looked out over this vast expanse of Central Station track, and he sort of said, 'that's been sitting there for 100 years, largely unchanged, and you've got tumbleweed blowing up and down one of the city's most precious real estate assets','' Mr Cameron says of their first meeting.

''He said across the two shelves of my office is the last 40 years' worth of inquiries into Sydney's mass transit network and he said your concept - and he said I've read every one of them - your concepts are better than any of their concepts.''

The plan may sound outlandish but making use of Chinese finance and engineering ingenuity is a challenge and a goal for governments in Australia, struggling with the cost of big engineering projects.

For instance, Chinese consortiums tried to bid on the $8 billion north-west rail link but failed to get past the first stage.

Chinese financiers were lining up to join the Aspire Sydney project, Mr Cameron says, including the multibillion-dollar China Glory International Investment Group.

''Having moved 400 million people from the countryside to cities over the past two decades, we have acquired confidence in city building at high speed and low cost,'' Xin (Charles) Zhang, the group's chairman, wrote to Mr Cameron in an email.

A spokesman for Mr Abbott said he would not comment on "private conversations", adding that the federal Coalition had committed $1.5 billion to WestConnex.

A spokesman for Mr Wielinga said he advised Mr Cameron to lodge the plan as an unsolicited proposal "if he felt it had promise". But in November last year the Premier's Department told Mr Cameron the proposal "did not present a commercial or financial proposition for [the] government to consider".

The radical option: how the developers want it to work

The Aspire Sydney consortium would build the M4 East motorway in exchange for the rights to develop more than 150 hectares of ''under utilised'' government-owned rail land between Central and Strathfield.

At least 150 high-rise towers prefabricated in China and hundreds of smaller buildings would be assembled along the corridor.

But it would require dismantling kilometres of existing train line to the western suburbs.

Mr Cameron's vision, outlined in 53 pages of details and drawings, involves replacing the current six lanes of track west of Central to Strathfield with new lines sunk underneath Railway Parade and the existing rail line in the inner west, laying in prefabricated ''tubes'' and train stations.

The M4 East roadway would run along much of the surface on an elevated platform, underneath which parking and commercial space would be created.

And how would the materials be put in place?

By building a new port.

Construction material would be shipped to a prefabricated port at Blackwattle Bay, near Glebe. To avoid bringing traffic to a standstill, it would be run to and from the building site on an overhead conveyor system along Wattle, Abercrombie and Cleveland streets.

The state government rejected the proposal in November but proponent Ross Cameron will not go quietly. He has called on state and federal politicians, and the people of Sydney, to give the plan a fighting chance. It should be fully evaluated, he says, adding that anything less would be ''a tragedy and a gross injustice''.

''Sydney faces a choice right now, a window of opportunity that will close,'' he said.

''If this thing is killed before it takes its first faltering breath, I will regard that as a terrible waste of opportunity. I will regard that as a lack of maturity in our democracy.''