28 January 2016
The Department for Business, Innovation and Skills said work from Sheffield, which includes policy development, will move to London.
Senior officials also say they will be withdrawing from other sites across the UK, putting a further 100 jobs at risk.
Under the plans, which the union will oppose, Sheffield would shut in January 2018. The department's 'BIS 2020' proposals are also likely to have major implications for partner organisations it works with.
PCS general secretary Mark Serwotka said: "The business department is supposed to lead the way in helping local economies grow after the recession, yet it is retreating from towns and cities across the country.
"We do not accept the need for these offices to close and for jobs to be at risk and will be opposing these moves."