Staff at Fujitsu have overwhelmingly voted to take industrial action over jobs, pay and pensions.
Trade union Unite, which represents the staff, said 92 percent were in favour of industrial action. Three quarters wanted to strike.
Workers are angry at the company's plans to close its defined benefit pension plan to future accruals. Such a move would affect 4,000 UK employees, Unite said, and effectively reduce their pay package by an average of 20 percent.
"The company intends to force this through by dismissing employees after the end of the consultation period in November, and offering them employment on new contracts which are unchanged except in relation to pensions," the union said in a statement.
Fujitsu announced 1,200 redundancies in August, and also has an ongoing pay freeze. But Unite said that in total 6,000 staff -- nearly half of Fujitsu's UK workforce -- were "at risk" of losing their jobs as the consultation progresses and decisions are taken.
Fujitsu's main sites are at Bracknell, Stevenage, Manchester, Crewe, Belfast, Staines, Basingstoke, Wakefield, Sheffield, Solihull, Slough, Lewes, Warrington, Cardiff, Bristol, Newcastle and London.
Peter Skyte, national officer at the union, said: "Fujitsu remains a highly profitable company, and our members are insisting that the company must treat them fairly and increase pay, provide decent pensions, and consult meaningfully to minimise job losses and avoid compulsory redundancy."
Fujitsu declined to comment, citing the ongoing consultation period.