The conference has seen protests over pay and calls for a windfall tax
The government's welfare reform plans have been criticised as a "fundamental attack on the welfare state", on the last day of the TUC conference.
Union delegates described plans to make unemployed people work for benefits and axe incapacity benefit as "sickening".
They approved an emergency motion opposing the welfare green paper and pledged to hold nationwide rallies.
The government hopes the plans will reduce those on benefit by a million over the next seven years.
The comments came on the final day of the TUC's annual conference in Brighton, where delegates have also been calling for an end to the government's policy of capping public sector pay rises at 2% - and urging a windfall tax on the big energy companies.
On Thursday they voted to oppose the welfare reforms and stage a lobby of Parliament and nationwide rallies.
The government's plans to scrap Incapacity Benefit and make those jobless for more than two years work full-time in the community are included in its Welfare Green Paper. The government says the plans will "transform lives" and help achieve its target of an 80% employment rate.
But Public and Commercial Services Union general secretary Mark Serwotka said the reforms "expose the depth to which the New Labour government have sunk".
He added: "This is the first time since 1948 that any government has seriously proposed abolishing the safety net benefit for those without any means of financial support.
"The government is proposing to cut the benefits of the long-term sick and disabled - a fundamental attack on the welfare state."
And he reserved some anger for Work and Pensions Secretary James Purnell, whom he described as the most "disgraceful" member of the Cabinet.
Phil Davies, national officer of the GMB union, said the unemployed were "being treated like villains".
Also on the final day Unite general secretary Derek Simpson warned delegates that a number of legal decisions made in Europe could have "disastrous consequences" for workers' rights in Britain.
He said decisions by the European Court of Justice could set a legal precedent that would stop unions defending workers' pay and conditions.
The conference ended without the traditional singing of Auld Lang Syne at the finale - which has ended most conferences for the past 140 years. TUC president Dave Prentis told delegates they were "modernising" and instead a video of the highlights of the week was played.