The Pew Research Center survey was released the same day an Indiana University study said millions of Americans fell below the poverty line during the Great Recession and millions more would be forced into poverty, even as the nation emerges from the downturn.
The Pew survey found 66 percent of Americans say they believe "very strong" or "strong" conflicts exist between the rich and the poor, a 19 percent jump from 2009.
The 30 percent who say class conflicts are very strong is double the proportion who said the same thing in July 2009 and represents the largest share expressing this opinion since the question was first asked in 1987, the non-profit Pew center said.
In 2009, more survey respondents said there were strong conflicts between immigrants and native-born Americans than said the same about the rich and the poor. Other traditional sources of tension are race and age.
Younger adults, women, Democrats and blacks are somewhat more likely than older people, men, Republicans and whites or Hispanics to sense class tension, the survey of 2,048 adults interviewed Dec. 6-19, 2011, indicated.
But the number of Republicans seeing class tension increased substantially to 55 percent, up from 38 percent in 2009, even as the GOP leadership has railed against the concept of class divisions.
Yet the growing sense of class tension does not necessarily signal an "increase in grievances toward the wealthy," despite a belief rich people have advantages poor people don't, a report on the survey said.
Forty-six percent of respondents say they believe most rich people "are wealthy mainly because they know the right people or were born into wealthy families," the survey found.
But nearly as many -- 43 percent -- say wealthy people became rich "mainly because of their own hard work, ambition or education," largely unchanged from a 2008 Pew survey.
The current survey's margin of error is 2.9 percentage points overall and 4.4 percentage points for adults 18 to 34.
Class-conscious attitudes are generally shared, regardless of income level, the study also found.
Sixty-four percent of all adults with family incomes of less than $20,000 a year report serious conflicts between the rich and poor -- a view shared by 67 percent of those earning $75,000 a year or more.
A separate Indiana University study said the number of Americans living below the poverty line surged 27 percent since 2006, the year before the Great Recession began, driving more than 10 million people into poverty by 2010 and millions more last year, even though the recession technically ended in mid-2009.
Poverty will likely increase because the economic downturn's many hardships can be expected to force many more people in to poverty, said the study, "At Risk: America's Poor During and After the Great Recession," conducted by Indiana's School of Public and Environmental Affairs.
These hardships include social safety-net cuts due to growing federal and state deficits and inferior quality and pay for newfound jobs, the study said. Other hardships often cited include a continuing decline in home values and increase in foreclosures and personal bankruptcies, coupled with rising gas and food prices.
It is difficult for people in poverty to climb out of it again, the study said.
The 12 hardest-hit states are Florida, Nevada, Arizona, Michigan, Indiana, Ohio, California, Connecticut, South Carolina and Minnesota, North Carolina and Wyoming, the study found. The last three states tied for 10th in their poverty-rate increases, the researchers said.