Seventy percent of U.S. voters think it was wrong to let China host the Olympics, but equal numbers say a Beijing Games boycott would fail to change China's human rights policies, a Zogby poll showed on Tuesday.

The survey of 7,121 likely voters conducted April 4-7 found widespread doubt that a boycott would have any effect on China and strong expectation that China's communist government would prevent critical media coverage and try to punish reporters who portrayed the country in a bad light.

The online survey poll found that 48 percent of respondents think U.S. officials should boycott the opening ceremony of the Aug. 8-24 games because of China's human rights record, while 33 percent believe the officials should attend.

Zogby International said 31 percent believe the U.S. Olympic Committee should boycott the Beijing Games and 23 percent think President George W. Bush should order a U.S. boycott to protest China's record on human rights.

The poll was published a day after U.S. Democratic presidential candidate Hillary Clinton urged Bush to boycott the Beijing opening ceremony unless China improves human rights.

Bush, who accepted an invitation to Beijing from Chinese President Hu Jintao, has consistently resisted suggestions he rethink his plans and said he can raise U.S. concerns about human rights directly with the Chinese leader.

The survey, which follows weeks of protests by Tibetans, contrasted with a May 2007 poll in which 44 percent approved of the International Olympic Committee's decision to award the 2008 Olympics to Beijing, while 39 percent disapproved.

But the U.S. polling agency said it found significant doubt among American voters about the effectiveness of any boycott.

Seventy percent believe a Beijing Games boycott would "amount to grandstanding by world leaders that might help them politically in their own countries, but will have no effect on how China's leaders treat their own citizens," it said.

Only 13 percent believed a boycott would "embarrass the Chinese leadership so much they would change how they treat Chinese citizens," said Zogby.

The polling group said 71 percent of respondents believed any U.S. boycott of the Beijing Games would be hypocritical because the United States imports so many products from China and retains close diplomatic ties with the country.

Forty-eight percent of poll respondents voiced concern that the U.S. and international media would limit negative coverage of China before and during the Olympics because they fear reprisals from the Chinese government, Zogby said.

Nearly all respondents - 94 percent - said they believed the Chinese government would try to prevent international media from covering stories that portray China in a bad light, and 78 percent thought Beijing would try to punish those who produce stories that reflect negatively on China, Zogby said.

The poll had a margin of error of 1.2 percentage points.