The industrial action, which saw picket lines mounted outside jobcentres and benefit offices across the country, was expected to spread today as driving examiners stage their own walkout over low wages.
The Public and Commercial Services union (PCS) estimated that 90,000 staff from the Department for Work and Pensions went out on strike following the collapse of peace talks aimed at resolving a long-running pay dispute.
The strikers' anger was worsened by the leak of a report from the head of an efficiency review for the government suggesting that up to 80,000 civil service jobs could be axed.
Mark Serwotka, the PCS general secretary, said the union would fight any move to cut jobs and complained that the civil service had become an "easy target" for politicians.
He confirmed that the strikes had been supported by up to 90% of union members, closing jobcentres and benefit offices and reducing services in others.
"Civil servants are sick of the lack of recognition for their hard work. They deliver frontline public services but are regularly exposed to contempt from politicians who fail to understand the important work they do.
"I'm very disappointed that we have had to take strike action to defend members' interests; however, civil servants are simply no longer prepared to accept poverty wages," he said.
The department played down the impact of the action, saying 90% of Jobcentre Plus offices had remained open.
The PCS estimates a quarter of staff at the department earn less than £13,750 and 81% are paid less than the UK average for non-manual workers of £24,000.
Mr Serwotka said last night: "We have far too many members administering government benefits that they also have to claim just to scrape together a living.
"I call on ministers in all the departments involved to step in and release the money to resolve this dispute."
The 48-hour strike is the most extensive in the civil service since a 1991 walkout over "market testing" and privatisation.
Union's case
The two-day strike action follows:
· A 2.6% cost-of-living pay rise for staff at the Department for Work and Pensions
· An offer of a 2% cost-of-living rise at the Driving Standards Agency
PCS claims endemic low pay in the civil service:
· Starting salaries for frontline jobcentre workers start at £10,000; those on the lowest DSA grade earn £10,250
· Many DWP staff rely on the very benefits that they administer
· Around 90,000 DWP staff earn less than £15,000
· The PCS says that the DWP pay offer for 2003 included a discriminatory performance scheme which predetermines that half of the staff will be rated annually as poor, irrespective of their individual performance
