The Public and Commercial Services Union (PCS) is balloting 280,000 workers in more than 200 government departments about industrial action.
The union wants to hold a one-day strike on 31 January. It said staff are angry about job cuts, outsourcing, and low pay.
With the first compulsory redundancies already announced at the Department for the Environment, Food and Rural Affairs and Department of Trade and Industry, the PCS fears that more compulsory redundancies in greater numbers will occur elsewhere across the Civil Service.
Mark Serwotka, PCS general secretary, said: “The government’s refusal to give guarantees on compulsory redundancies runs contrary to numerous multinationals such as, Siemens, Kelloggs and the privatised rail companies.
“In an organisation as big as the civil service, with 500,000 staff, guarantees on compulsory redundancies should be even easier to give than those given in the private sector.”
Serwotka warned that staff morale had “plummeted” and anger grown at below-inflation pay offers.
The government said it would do everything it could to avoid compulsory redundancies, but there could be no cast-iron guarantees.