The Government has been accused of spreading "prejudice and ignorance" over benefits after new research showed the public was hostile to welfare.
A poll by the TUC revealed that more than two out of five people believed benefits were too generous, while three out of five agreed that the UK's welfare system had created a culture of dependency.
The survey of 1,800 adults came amid a political row over welfare spending ahead of a Commons vote next week on plans to impose a real-terms benefits cut.
The TUC said its poll also showed that once people became aware that the benefit uprating cap will hit workers in low-paid jobs, they were less likely to support the Government.
The union organisation said its study discovered "widespread ignorance" about spending on welfare, the level of benefit fraud and the generosity of payments.
TUC general secretary Frances O'Grady said: "It is not surprising that voters want to get tough on welfare. They think the system is much more generous than it is in reality, is riddled with fraud and is heavily skewed towards helping the unemployed, who they think are far more likely to stay on the dole than is actually the case.
"But you should not conduct policy, particularly when it hits some of the most vulnerable people in society, on the basis of prejudice and ignorance, and it is plainly immoral to spread such prejudice purely for party gain, as ministers and their advisers are doing, by deliberately misleading people about the value of benefits and who gets them.
"Voters who have a better grasp of how benefits work and what people actually get, oppose the Government's plans. When people learn more about benefits, support moves away from coalition policy.
"The truth remains that benefits are far from generous, the vast majority of the jobless are desperate for work and most benefit spending goes either on pensions or on benefits for those in jobs or who aren't able to work."