More workers will go on strike over Tata Steel’s plans to cut thousands of jobs in its efforts to make greener steel in south Wales.

The GMB union said a ballot of it members at the steel giant saw 72% vote in favour of industrial action.

Unite members at Tata Steel’s Port Talbot and Llanwern site will begin a “work to rule” and overtime ban on 18 June over plans to close both blast furnaces with the loss of 2,800 UK jobs.

Tata Steel called the results of the vote “natural disappointing” and previously warned it could withdraw enhanced redundancy packages if workers go on strike.

“These brave workers have said clearly they won’t go down quietly,” said Charlotte Brumpton-Childs, a GMB national officer.

“Whilst Tata seem determined to douse the heat of our blast furnaces, the fire burns within our members’ hearts,” she added.

Tata Steel is proposing a £1.25b investment – including £500m from the UK government – to build an electric arc furnace at its Port Talbot site, producing less carbon than the current blast furnaces, but employing fewer people.

A spokesperson said the current operation in Port Talbot losses of more than £1 million a day and at the end of its life, making is unreliable and inefficient.

“Our ambition remains to move forward at pace with a just transition, and to be at the centre of a future green industrial ecosystem in the UK,” they added.

The Community union, which represents the bulk of workers at Port Talbot, has told its members that it is considering an improved redundancy offer which it will put to them once negotiations are completed.