Workers at computer giant Fujitsu are to stage six strikes in a row over job cuts, a pay freeze and pension changes.

Union Unite said the walkouts on December 18 and January 7, 8, 11, 14 and 15 would be the first national strike in the IT sector in the UK. The union is protesting over proposals for 1,000 redundancies, a pay freeze imposed earlier this year and plans by the company to close the firm's main final-salary pension scheme to future staff.

They proposed job losses include 100 redundancies in Bristol, where Fujitsu staff and recruitment agency Kelly Services provide IT helpdesk services for Lloyds TSB.

Lloyds, which took over HBOS in a £12-billion deal in January, wants to combine the Lloyds helpdesk, which employs 243 people, with the existing HBOS centre in West Yorkshire. But it only wants 140 extra staff to move over to HBOS, leaving at least 103 staff without a job.

It is also thought Bristol-based staff will be reluctant to relocate, meaning the number who are left without a job will probably be higher.

Unite said it planned to stage a "Scrooge" protest outside Fujitsu's London headquarters on December 18, contrasting the company's treatment of staff with last year's £200 million profit and money paid out to two directors as "compensation for loss of office".

Joint general secretary Derek Simpson said: "Whilst we remain ready and willing to talk at any time, this further rejection of the company's position leaves no doubt – our members saying enough is enough.

"We recognise the effect any industrial action will have on key private and public sector customers and clients of Fujitsu, but the responsibility for this rests squarely with the company for failing to address the issues."

Fujitsu employs around 11,500 people in the UK.