Thousands of Jobcentre staff are going on strike in a row over working conditions and management targets.
Members of the Public and Commercial Services union (PCS) in 37 call centres are staging a 24-hour walk-out on Monday.
They have accused management of showing "little willingness" to try to resolve the dispute.
The Department for Work and Pensions (DWP) has said it is disappointed at the decision to take industrial action.
The action follows a two-day strike by union members at seven centres in January.
The DWP announced a revamp of its telephone and benefit processing service in October 2009.
The January action started after a decision to convert seven benefit processing offices into "contact centres", with staff re-allocated to taking calls from the public.
Since then the dispute has broadened to include staff at all 37 contact centres.
In a ballot in March of the union's 7,000 members who work in call centres, 70% of those who took part voted for strike action. The vote had a turnout of 43%.
Although talks continued, they broke down earlier this month.