British billionaire businessman Sanjeev Gupta is planning a major investment in the city of Whyalla.

Mr Gupta, considered the city’s saviour for buying its financially troubled steelworks last year, announcing plans to increase its production.

Mr Gupta says he is now investigating the possibility of building a copper smelter and refinery.

He also owns a controlling stake in South Australian-based renewable firm Zen Energy.

Mr Gupta says his copper smelter plan is “strongly viable”.

“What it needs is good infrastructure, which we have,” Mr Gupta said.

“It needs cheap energy, which we will have.

“It needs a great workforce, which we have and can develop more of, and it needs the supply of copper [concentrate], which we've had some interesting discussions with vendors for that.”

Mr Gupta said more details would be released before the end of the year.

“We've hired and will join within a month-and-a-half a new CEO who will head this objective, so it's still in development but we're very serious about it,” he said.

Mr Gupta also has plans to buy or set up a bank in Australia aimed at servicing medium-sized businesses, as he has done in the UK.

“Because it's too expensive to serve that sector, there's a gap in the middle and we felt that gap very acutely in the UK and we addressed that,” he said.

“In the UK, we've bought two banks in the UK and repurposed them.

“We'd prefer to do that here, because it means we can short cut the timeline and set up a bank, but if we have to set up, we'll apply for a licence and set up from scratch.”