JUST how many workers the foreshadowed closure of Tomago Aluminium will affect downstream remains unclear, but industry insiders, spectators, and experts all agree it will be devastating for direct employees.

Unions have described the potential shutdown as a gut punch for the Hunter, throwing thousands of families, rightfully concerned about what the future holds, under a bus.

Electrical Trades Union (ETU) NSW/ACT Secretary Allen Hicks said it would have a devastating impact on the broader community and warned that consultation must be genuine, not a cover for a decision Rio Tinto has already made or as an avenue to attack the viability of renewable energy.

"We're bound to see some attempt to use this consultation period as fuel for their anti-renewable rhetoric, but that's nothing but scaremongering," Mr Hicks said.

"If the NSW Government is serious about delivering a secure, cheap energy future for the state and the industries we rely on, it needs to start by putting our power back in public hands.

"Privatisation has driven power prices up in NSW," Mr Hicks said.

"Households have been paying the price of that for years. Now thousands of families are also paying with their livelihoods.

"Australia can power industries like Tomago cleanly and reliably if governments and companies do their job. Workers and communities shouldn't have to pay the price for corporate greed and political failure."

His comments, and those of other industry insiders, unionists and advocates, come in the wake of an announcement on Tuesday (October 28) from Tomago Aluminium chief executive Jerome Dozol.

Mr Dozol said they had begun a consultation process with employees about the future of its operations after failing to identify a pathway that supports commercially sustainable operations beyond 2028.

Mick Forbes, Newcastle and Northern NSW sub-branch secretary for the Transport Workers Union, said up to 120 drivers would be affected by a closure, many of them sub-contractors, as well as operators such as K&S Freighters and Crawfords and their workers.

"A lot of them rely heavily on that transport chain," Mr Forbes said.

"In transport, we are vulnerable to any kind of change in contracts, but there is no immediate recovery from a closure because that line of work is not just changing hands; that's the end of it.

"The way we look at it is that's 120 families affected, and depending on their situation, that is, for example, if they are a company employee, there might be an opportunity for them to work in a different role, but a percentage is likely to be made redundant, and contractors are in a little bit of a worse position.

"They've got to work out where their remuneration is going to come from. Quite often, their vehicle is borrowed against their house, so not only can they not put food on the table, but they also lose their house. And so it can have really dire consequences, and it's of great concern."

Phillip O'Neill, a Herald columnist and professor of economic geography at Western Sydney University, said it was very difficult to put a dollar figure on what the downstream impacts of a Tomago closure were, and most likely it was "hugely exaggerated".

But that did not diminish the massive impact on the workers and the hundreds of contractors affected.

"Each of those workers would be one hundred per cent unemployed as a consequence of Tomago closing at any period of time it takes them to find a new job," he said.

"So you can never underestimate the impact of a closure, because its impact on a worker and their family is brutal."

Older workers with skills and roles very specific to that smelter would find it more difficult to find another job and may be forced into early retirement, compared to the younger, more formally skilled workers who were likely to find other work more easily, he said.

The government copped a spray about the issue from Senator Ross Cadelle in parliament, who said Tomago employs 1400 people to produce aluminium, and has "kept the region strong"

"It's kept other businesses strong and it's been so important," Mr Cadell said.

The government had used Tomago as a photobackdrop to announce its new low-carbon aluminium production scheme, and now had a responsibility to its workers, Mr Cadell said.

"When you use it as a backdrop, when you use it as a showpiece, when you use it as an excuse, you have to back it up," he said.

"If Labor's all-renewable approach is going to deliver the cheapest form of energy, why did we need to volunteer $2 billion worth of taxpayers' money to keep an energy-reliant business open.

"And so now we see 1,400 jobs being flushed because your energy policy, your 100 per cent renewable, is a crock ... All you want is a grab of net zero. Net zero. You have to face the consequences when people leave. The blood is on the hands of the Labor Party."