WASHINGTON (Reuters) - China's blocking of Web sites has embarrassed the International Olympic Committee, but a computer security expert said on Thursday that visitors to Beijing also needed to protect their data from prying eyes.

"People who are going to China should take a clean computer, one with no data at all," said Phil Dunkelberger, chief executive of security software firm PGP Corp.

Travellers carrying smart cell phones, blackberries or laptop computers could unwittingly be offering up sensitive personal or business information to officials who monitor state-controlled telecommunications carriers, Dunkelberger said.

He said that without data encryption, executives could have business plans or designs pilfered, while journalists' lists of contacts could be exposed, putting sources at risk.

Dunkelberger said that during unrest in Tibet in March, overseas Tibetan activists found their computer systems under heavy pressure from Chinese security agencies trying to trace digital communications.

"What the Chinese tried to do was infiltrate their security to see who in China the Tibet movement was talking to," he said.

China's security policies clashed with Olympic norms on Thursday, when IOC officials said they were embarrassed by last-minute disclosures by the Chinese government that media covering the August 8-24 Olympics would not have unfettered access to the Internet.

On Tuesday, U.S. Sen. Sam Brownback, a Kansas Republican, said China had installed Internet-spying equipment in all the major hotel chains serving the Olympics.

Citing hotel documents he received, Brownback said journalists, athletes' families and others attending the Olympics next month "will be subjected to invasive intelligence-gathering" by China's Public Security Bureau.

Dunkelberger, whose firm serves many multinational corporations operating in China, said, "A lot of places in the world, including China, don't have the same view of personal space and privacy that we do in the United States."

"You've got to suspect that every place you're doing work is being monitored and being watched," he said.

His advice for Travellers was to keep their electronic devices in the their possession at all times, and if they could not take a clean computer, be sure to encrypt the computer, files and even e-mails.

"Whether it's a file or an e-mail, if you're worried about it, you should probably encrypt it," Dunkelberger said.

(Editing by Peter Cooney)