Monday's announcement came after months of uncertainty and negotiations.

Premier Peter Gutwein said he couldn't keep the smile off his face after hearing the news.

"As a major regional employer, the securing of the ongoing operation of the smelter and the site's 250 jobs is welcome news, not only by TEMCO employees and their families, but also by the broader community," Mr Gutwein said.

"Tasmania has what the world wants in clean, renewable energy and the purchase of the site will help GFG Alliance achieve their goal to be carbon-neutral by 2030."

Mr Gutwein confirmed the state government had offered GFG Alliance financial assistance to aid in the purchase.

"We're working with GFG, in principle we've agreed to stamp duty relief in terms of the purchase," he said.

"That's being worked through at the moment, and once that's been finalised we'll release what that number is."

George Town Mayor Greg Kieser said it was a "really amazing point in time" for the region.

"It really signifies in both the manufacturing winds as well as the economic winds that are blowing into Tasmania and the north in general," he said.

"I think as the world starts to grasp the challenge of decarbonisation, more and more companies will realise the opportunity that green energy and Bell Bay in the north of Tasmania represent.

"There is an extreme amount of interest and I want to compliment both the state and federal government in their vision and leadership in creating a climate which is absolutely set for a higher level of investment and the prosperity and the jobs that these things are going to drive over the next coming decades."

Bell Bay Advanced Manufacturing Zone chief executive Susie Bower said the purchase was encouraging to drive future investment into the area.

"We have Fortescue that are actually going to be making a decision by June this year around investment for a 250 megawatt facility with hydrogen, that will actually be the largest in the world," Ms Bower said.

"We have Woodside that are looking at starting construction in the third quarter of this year, and we still have Able Energy and Origin starting their feasibility studies.

"So the future is extremely bright, all of those areas, all of those companies bring around 100 jobs each, so the future is extremely bright for Bell Bay and where else would you want to be right now but Tasmania."