Thousands of workers at Tata Steel plants in the UK are scheduled to go on strike for a day on 22 June following a dispute over pension.
The Community Union, in a statement, said the strike action will be preceded by "action short of strike action involving an overtime ban and a work to rule," from around the middle of next week.
According to the BBC, Tata has four sites in Wales - in Port Talbot, Newport, Flintshire and Carmarthenshire - as well as sites in England including Corby, Hartlepool, Rotherham, Scunthorpe, Teeside and York.
The broadcaster quoted a Tata Steel spokesman as saying: "We have been trying to develop an affordable and sustainable pension schemed for employees so we are very disappointed by today's announcement on strike and industrial action.
"Everyone agrees that changes need to be made to resolve the challenges facing our pension scheme, which has a projected shortfall of over £2bn [€2.72bn, $3.07bn]. We will soon be announcing new measures which will lessen the impact of the proposed pension changes, particularly on our longest-serving employees nearing retirement age."
13,000 workers involved in the dispute
The Guardian says that about 13,000 workers are involved in the dispute over the proposed closure of their final-salary pension scheme.
The threat of a strike is seen as a potential deterrent to future investments in the UK steel industry, which has been struggling to operate profitably despite government help, Reuters reported.
India's Tata Steel Ltd posted an $889m quarterly loss on 20 May, inflated by a huge impairment on its UK business, the news agency said.
In a statement, the National Officer at Unite, Paul Reuter said: "We are still open to talks if Tata are prepared for meaningful discussions. We have offered Tata the savings it says it needs. But the company wants to close the scheme altogether. This is not acceptable to workers, which is why industrial action will start next week."
In the UK, unions must give seven days' notice of any industrial action.