Unions representing Tata Steel workers in Port Talbot are to ballot members over industrial action in response to a plan by the company to close their pension scheme.
Tata Steel announced plans to close the final salary pension scheme on Friday.
Trades unions accuse Tata of being “hell bent” on closing the pension scheme, and say the company is refusing to compromise.
Tata said it will consult workers on the proposal.
A company spokesman said: “We have been unable come to an agreement that would have enabled defined benefit provision to continue.
“We remain committed to providing employees with competitive future pension provision.”
Tata is proposing to replace the existing pension scheme with a defined contribution one.
Roy Rickhuss, general secretary of the Community trade union, said Tata’s decision to close the scheme was “unnecessary and profoundly disappointing”.
He said: “We have made every effort to compromise with the company, even discussing the possibility of meeting the deficit through changes to member benefits. Sadly, the company rejected this offer.
“We have lost all faith in the company and its leadership, which has brought us to the brink of a major national industrial dispute for the first time in over 30 years.
“We feel we have no option but to consult our members and prepare to ballot for industrial action to defend their hard-won pension rights.”
The decision to seek a mandate for industrial action was taken at a meeting in London of trades union representatives from across Tata Steel’s UK operations
Tata Steel insists it is co-operating with the unions.
“The discussions have been held in a constructive and transparent atmosphere,” said a spokesman.
A 60-day consultation on the changes begins on March 23. Tata Steel is proposing to close the pension scheme in April next year.