Up to 270,000 civil servants are to stage a national two-day strike in a bitter row over redundancy pay.
Members of the Public and Commercial Services Union will walk out on March 8 and 9, with the threat of services being hit by industrial action throughout March.
The strikes will involve jobcentre staff, tax workers, coastguards, border agency officials, court staff and driving test examiners. They follow a long-running row over changes to the civil service compensation scheme.
Union members voted by 63% in favour of stoppages, with 81% backing an overtime ban.
The union complained that changes to redundancy and compensation arrangements will see staff "robbed" of up to a third of their entitlements and see civil and public servants lose tens of thousands of pounds if they are "forced" out of a job.
The union's national executive committee will be meeting next week to finalise further strike dates, which could include national walk-outs and targeted strike action.
General secretary Mark Serwotka said: "These cuts, which will see loyal civil and public servants lose tens of thousands of pounds if they are forced out of a job, are more about crude politicking than making savings.
"We have suggested ways in which the Government can make these savings whilst protecting the rights of existing members, yet it seems intent on penalising the people who keep this country running.
"With civil and public service jobs increasingly at risk, this is a cynical attempt to cut jobs on the cheap which will ultimately damage the services we all rely on. The Government needs to recognise the depth of anger which has been demonstrated."
Other civil service unions have reached agreement with the Government over redundancy pay.