Thousands of Jobcentre Plus staff are to stage a 24-hour strike in an escalating row over working conditions and a "target driven culture".
Members of the Public and Commercial Services union based in more than 30 call centres across the UK will walk out on April 18 after accusing management of showing "little willingness" to resolve the dispute.
In a ballot of the union's 7,000 members in the call centres, 70% of those who took part voted for strike action, with a turnout of 43%.
The strike will hit call centres including those in Glasgow, Dundee, Newport, Bridgend, Bangor (north Wales), Sheffield, Halifax, Norwich, Southend, Newcastle upon Tyne, Middlesbrough, Blackpool, Liverpool, Manchester, Nottingham, Derby, Coventry, Exeter and Bristol.
The action follows a two-day strike in January by more than 2,000 workers in Jobcentre Plus's seven newest contact centres who complain of being forcibly moved from processing benefit claims to handling inquiries by phone.
The union said it wants to improve the levels of customer service in call centres, end a target driven culture, particularly by changing the way "unrealistic" average call times are used, and introduce proper flexible working arrangements.
Jane Aitchison, the union's Department for Work and Pensions group president, said: "We are being prevented from providing a good quality service to the public because of unnecessary and unrealistic call centre targets."
"We entered into negotiations in good faith because we care about the help and advice we give to some of the most vulnerable people in society. It's very disappointing that our management didn't do the same."
PCS general secretary Mark Serwotka said: "With unemployment rising and welfare recipients being blamed for an economic crisis they did not cause, it is outrageous that standards are being driven down in Jobcentre Plus. Instead of punishing people who are claiming benefits through no fault of their own, the Government should be investing in our public services to help get people back to work quicker and to help our economy to grow."
A DWP spokesman said: "We are disappointed that despite three-quarters of staff across the centres not voting to strike, the PCS has decided to take industrial action. The contact centre staff at DWP have good terms of employment including generous holidays, and have a good amount of flexibility. But we have to ensure that our service is available when our customers, who include some of the most vulnerable people in the country, need us."