Union leaders have claimed an 85% or more response in Scotland to a 48-hour strike by JobCentre and benefit office workers.
A closure sign at a central Scotland JobCentre
However, managers claimed that 59% of staff had gone on strike in Scotland.
The UK Department for Work and Pensions (DWP) plans to axe 30,000 posts by 2008 as part of moves to modernise services.
The Public and Commercial Services union (PCS) said 15,000 UK job losses since 2004 meant critical services were on the verge of collapse.
The DWP claimed only eight of its 150 offices in Scotland were closed.
Most of the others were able to offer a near-normal or partly-reduced service, it insisted.
The offices closed were said to be at Castle Douglas, Cumnock, Dingwall, Invergordon, Forres and three in Edinburgh.
The department said robust contingency plans had been put in place to maintain services and ministers remain committed to their efficiency programme.
A spokeswoman said: "It is unhelpful and pays little respect to the work of our staff to describe the service as being in crisis."
She referred, instead, to "service delivery pressures".
PCS Scottish chairman Sam Hall called on ministers to review the impact of the cuts on vital services.
He said: "We understand and accept that the government has an efficiency programme.
"We're prepared to sit down with them and discuss that programme but not to allow them to go ahead in the manner where they are arbitrarily axing jobs and closing offices.
"It denies access to the very services that the most vulnerable members of our society are in need of."
Eddie Reilly, Scottish secretary of the PCS, said: "Our members are not just striking to protect jobs, they are stopping for 48 hours to prevent the savage butchery of services which are absolutely critical to the most vulnerable in our society."
The union leader said the shake-up would not be tolerated and called for it to be stopped while further cuts were assessed.
He echoed the demand for UK ministers to "objectively review the position" with the union.
"At a time when [Prime Minister] Tony Blair is seeking to redefine the welfare state, the people of Scotland have to ask the question - in whose interest is he acting?" he said.
Mr Reilly, who predicted "massive" support for Friday's stoppage, claimed that consequences of cutbacks included nine weeks of incapacity benefit referrals outstanding in Glasgow, and only 60% of people being paid the right amount of money at any time.
The union also claimed that more than 24% of jobseekers' allowance claims, and more than 19% of income support claims, were dealt with inaccurately in Scotland.
The DWP spokeswoman dismissed the allegations, insisting it took 11 days to pay incapacity benefit in Glasgow and the "performance accuracy rate" for income support and jobseeker allowance was more than 90%.
Chancellor Gordon Brown announced the redundancies in March 2004, as part of wider civil service cuts aimed at boosting funding to frontline services such as doctors and nurses.