Whyalla's city council anticipates its population will "explode" from 22,000 to 80,000 in the next 10 to 20 years as the regional South Australian centre embarks on an ambitious upgrade to its steelworks and local infrastructure.

Key points: Whyalla steelworks owner Sanjeev Gupta has signed off on $600 million worth of projects

Whyalla steelworks owner Sanjeev Gupta has signed off on $600 million worth of projects The council is predicting the town's population will boom to 80,000

The council is predicting the town's population will boom to 80,000 Prime Minister Scott Morrison said it was a win for South Australia

At an event headlined by steelworks owner Sanjeev Gupta, the council today announced a $45 million hotel would be built on the Whyalla foreshore, as well as a $145 million horticulture development and a $6 million recycling business.

Mr Gupta's GFG Alliance announced new plans for a "mega" steel plant and that it had signed contracts worth more than $600 million as part of the transformation project.

That includes a new rolling mill — to replace the current 60-year-old infrastructure — to be completed in partnership with Italian metal industry firm Danieli to boost annual steel production.

"We will increase production to 1.8 million tonnes, that is a fairly modest steel plant in the global context of steel," Mr Gupta said.

"What is critical is value-added steel, we make things that add value so we can specialise in things we can sell at a good price to sustain the business."

Chinese corporations will play a major role in both the council's and GFG Alliance's plans.

A new pulverized coal injection plant to improve the plant's performance will be constructed by CISDI Engineering — a Chinese corporation run by the China Metallurgical Group Corporation.

Beijing Enterprises Clean Energy [BECE] will develop the $145 million horticulture facility to be powered by photovoltaic solar panels.

Sanjeev Gupta admits mega steel plant plans 'crazy'

GFG Alliance's Whyalla vision is similar to the design of this plant built by CISDI. ( Supplied: GFG Alliance )

The council's population estimate of 80,000 by 2040 is based on an ambitious vision to build a 'Next-Gen' mega steel plant that would be one of the biggest in the world.

Mr Gupta said the "very audacious, very brave" plan was in the feasibility study stage, and admitted some people would label it as "crazy".

"We will embark on a journey for a new grand-scale steel plant which will be one of the largest in the world," he said.

"People will say 'crazy concept'."

GFG Alliance said the project would be capable of producing 10 million tonnes of steel per year and would be based on "state-of-the-art technologies".

"We cannot be only a steel town," Mr Gupta said.

"As we develop, as we undertake our transformation project, we must continuously encourage partners, other players, to come and join in the development of this great city."

He said it was important to differentiate the transformation project from the Next-Gen project.

Anna Mareschi from Italian firm Danieli with Mr Gupta and SA Premier Steven Marshall. ( Twitter: Steven Marshall )

Whyalla City Council CEO Christopher Cowley said the population target of 80,000 was tied to Mr Gupta's vision to massively expand the steelworks.

"We make no excuses about being optimistic about the population potential for Whyalla," he said.

"If the Next-Gen plant takes off, that is where the 80,000 kicks in.

"We'd like to see a steady growth to that number — it is aspirational — but we're reaching for the stars."

Prime Minister welcomes investment

Earlier Prime Minister Scott Morrison described the town as the "comeback" city of Australia.

"A city with a future, that's where we are today, a city with a future," Mr Morrison said.

"South Australia now has the highest level of business confidence in eight years.

"This is the turnaround state in South Australia, and this is the comeback city of Australia, when we're talking about Whyalla."

Annual steel production is predicted to increase to 1.8 million tonnes. ( ABC News: Matt Coleman )

Opposition Leader Bill Shorten praised Mr Gupta's interest in the region, in addition to the workers of Whyalla.

"Sometimes it takes someone from outside to remind us how lucky we are and what we need to do to invest ourselves in the future," he said.

"I know the steelworkers of Australia, I know the steelworkers of Whyalla — you are highly skilled, you have coped with change… you've adapted to new technologies, you work in teams and you problem solve."

Premier Steven Marshall told the gathering of locals at the announcement that the town had got itself back on track.

"It wasn't that long ago that people thought the days of manufacturing were well behind us in Australia," he said.