Tens of thousands of civil servants will stage fresh industrial action later this week as part of a three-month campaign over pay, pensions and working conditions.
Members of the Public and Commercial Services (PCS) union working in most Government departments and agencies will strike for half a day on Friday.
Around 55,000 PCS members in HM Revenue and Customs will hold a half-day strike on the morning of Monday April 8, which is designed to disrupt the start of the new tax year.
The union's members in the Home Office, including UK Border Agency and Border Force workers, will strike all day on April 8.
The union held a strike on Budget Day last month and is planning further industrial action.
The union said it had asked for talks over cuts to civil service pay, pensions and terms and conditions, and accused the Government of refusing to negotiate.
General secretary Mark Serwotka said: "We said our Budget Day strike was not a one-day protest and this long weekend of walkouts is the next step in a series of strikes to put pressure on a government that is refusing to talk to us.