Talks aimed at saving jobs at Tata Steel have been described as “extremely positive” by the Unite union.
The new UK government’s negotiations with the firm over its restructure had previously been dubbed as “difficult” by Business Secretary Jonathan Reynolds.
Mr Reynolds pledged that the UK government has “got to try” to change the steel giant’s plans, which will cost 2,800 jobs.
Tata will close the second of its Port Talbot blast furnaces in September, citing losses of £1m a day.
Mr Reynolds met unions on Wednesday to discuss efforts to reach a “better deal” with the company.
The previous Conservative government pledged £500m to Tata Steel towards the cost of a new £1.25bn electric arc furnace which will melt scrap steel, but which requires far fewer workers than traditional blast furnaces.
The company closed the first of two blast furnaces on 5 July, and plans to shut the second in September.
Construction of the new furnace is scheduled to begin in August 2025.
“Our meeting this morning with Jonathan Reynolds was extremely positive,” said Unite general secretary Sharon Graham.
“The commitment given to achieving a sustainable, profitable UK steel industry is very welcome and, as was said this morning, decarbonisation must not mean deindustrialisation.”
She described the Labour government’s input as a potential “game changer”.
But, as Mr Reynolds told BBC Radio Wales Breakfast: “There is a lot more that this deal could do. I know it’s going to be difficult, but I think I’ve got to try.”
Delaying the proposed closure date of the second blast furnace was something he had already raised, Mr Reynolds said, but he accepted that Tata’s position had been “very unmovable” on that.
He said the talks were about “more than just the future of that last remaining blast furnace”.
“There are questions as to how quickly the transition happens, and the scale and size of the new furnaces that might be put in place,” he said.
“Steel is vital for a vibrant, secure economy and our steel sector needs a government working in partnership with trade unions and business to secure a green steel transition that’s right for the workforce whilst delivering economic growth.”
Tata Steel has reiterated its pre-election stance that it would press ahead with its plans, regardless of which party was in Downing Street.
UK chief executive Rajesh Nair said he would “be engaging with new ministers” over its “ambitious plans to invest in and transform Port Talbot” and “supporting our workers through this necessary but difficult transition”.
Proposals about future investment include discussions about a steel plate mill being built in Port Talbot, which could supply the materials to build wind turbines.
Labour campaigned on the promise of a £2.5bn fund for the future of the steel industry and has committed to continuing the previous government’s plans to provide £500m towards Port Talbot’s new electric furnace.