The construction of a fast rail network between Sydney and Newcastle could serve as a fillip for NSW's post-pandemic economy, an urban think tank has advised.
But the NSW government strategy for the long-discussed initiative is yet to be finalised.
The Committee for Sydney issued a statement on Monday to its members calling for the government to begin work on a Sydney-to-Newcastle fast rail line, and the use of such infrastructure to link the "Sydney Sandstone Megaregion".
This is the broader region of Greater Sydney and surrounds, stretching from Newcastle to the north, Wollongong to the south and the Blue Mountains to the west.
It argued the best thing governments could do to knit together the "megaregion", including for work and study opportunities, was to improve rail connections.
For a Sydney-to-Newcastle trip, fast rail reaching speeds between 200km/h and 250km/h could cut travel times from two-and-a-half hours to less than an hour.
The Sydney-to-Gosford route could take as little as 25 minutes.
This is distinct from "high-speed" rail, which surpasses speeds of 250km/h.
The Committee for Sydney said commutes of an hour or less were the "magic number" that encouraged significant interaction and travel between regions.
This would be even more important in the aftermath of the COVID-19 pandemic, given the development of hybrid working arrangements and growth in popularity of regional living.
Committee chief executive Gabriel Metcalf said NSW's tunnel boring machine - currently being used for the Sydney Metro tunnel projects - would be out of work in 2026.
This was the optimal time to get working on a Sydney-to-Gosford tunnel, he said, before extending the fast-rail network to Newcastle.
"Linking together the cities of the Sandstone Megaregion with fast rail means people have more choice - about where they work, where they live, and how they get around," Mr Metcalf said.
"Better connections across this geography means we effectively work like a bigger global city, with more economic gravitational pull."
The NSW government in the lead-up to the 2019 election said it would develop a fast-rail plan focused on regional centres including Newcastle and Bathurst.
It convened a panel chaired by British rail expert Andrew McNaughton to advise on the suitability of four routes: Sydney-to-Newcastle via Gosford, Sydney-to-Canberra via Goulburn, Sydney-to-Nowra via Wollongong and Sydney-to-Orange via Bathurst.
The report produced by the panel is yet to be released.
A Transport for NSW spokesman said in a statement that the government had been working on its fast rail strategy with experts and consulting with stakeholders.
"A strategy outlining the economic and social benefits of fast rail in NSW is being finalised, and once complete, will launch the next phase of this transformative regional development program," the spokesman said.
Premier Gladys Berejiklian also in the lead-up to the 2019 election said she'd like to see work on a fast-rail network begin by 2023.
Ms Berejiklian's office has been contacted for comment.
No Australian passenger train has ever exceeded 215km/h and most lines' top speed is 160km/h.
The Committee for Sydney hoped the government would finalise a business case for fast rail by the end of the year.