The proposed ‘mega-region’ – stretching from Newcastle to Wollongong through Western Sydney – could be a global economic powerhouse of 10 million people, the committee’s deputy-chair of the commission Professor Paul Wellings revealed.

“International experience has demonstrated the scale of the economic and social benefits that mega-regions can deliver without compromising the distinctive historical and cultural identities of their individual component cities,” Prof. Wellings said.

The panel has put forward a report suggesting Newcastle, Wollongong and Sydney link up to form what it called the “Sandstone” Mega-Region – after the geological bases of the three areas.

The report pointed out that places often thought of as a single city – like San Francisco or Hong Kong – are regularly part of a larger group of cities.

“All successful growing cities extend beyond their formal boundaries and are supported by other cities,” the report stated. “That is, behind every great city there is a network of other great cities.”

The report calls on planners to consider whether having Newcastle, Sydney and Wollongong develop as three separate cities is better than joining them together.

The Sandstone mega-region would also include over 70 per cent of the state’s population, as well as nearly 25 per cent of the national population, with three major trade ports in the proposed area all actually as “gateways to the world”.

The area would also boast eight universities, two of which are within QS’s top 50 universities worldwide, and six of which are included in the top 250.

But this mega-region won’t happen without a key addition to the eastern coastline – a one-hour train ride from the two regional locations to Sydney in the centre.

“Even a moderately fast rail network that reaches speeds of 200km/h could connect Newcastle, the Central Coast and Wollongong with Sydney in 60 minutes or less,” the report said.

A trip longer than an hour would make it impossible for the region to function as a single economic entity – which is the other key thing that has to happen for the mega-region to be a success.

Faster rails proposed could “slash” commuting times, the report reveals, including trimming the Newcastle to Parramatta travel time from “153 minutes to 60 minutes”, with networks creating new direct links between Newcastle and Parramatta, as well as Wollongong to Campbelltown and Liverpool.

Chair of the commission Kyle Loades urged those across the state to “realise their economic potential”.

“NSW is blessed with a set of dynamic and diverse regional centres. Enhancing the collections between our great urban centres could create a world-class mega-region of 10 million people, cutting-edge jobs and high-quality services,” Mr Loades said.

“The potential is real: let’s grasp this opportunity.”

The Sandstone report offers up similar predictions of the future to a ‘Megaregion 2101’ prediction from Australian Urban Design Research Centre’s Richard Weller and Julian Bolleter in 2013.

Weller and Bolleter’s now 5-year-old blueprint provided pathways to how Australia could accommodate its predicted population of 62.2 million 2101.

In their book Made In Australia - released March 2013 – the researchers proposed building three new cities along the east coast, including ‘‘New City X3’’ – an urban settlement that would encompass an area stretching from the north of Port Macquarie all the way down the coast to the southern reaches of the country’s capital in Canberra.

In the 2013 book, Professor Weller and Dr Bolleter suggested Newcastle be linked to Sydney by a 20-minute high speed train, which would be “crucial to decentralising the population along the coastline”.

Their prediction for a logical location for the new settlements along the rail corridor would be between Newcastle and Taree, as well as a link from the current NSW capital to Newcastle.

Although the Sandstone ‘mega-region’ plan focuses mainly on Newcastle, Sydney and Wollongong, Made in Australia suggested the massive future city would also encompass 17 regional cities including Bulahdelah, the Central Coast, Taree, Port Macquarie and Coffs Harbour.