BEIJING, Sept. 4 (Reuters) – Rio Tinto, Chinalco, Huiyuan, Coca-Cola, CNOOC and Unocal – a growing list of companies have had deals go awry inside China and out when politics and business mix, compounding the risks surrounding the deals.

Accusations of political interference and protectionism are lobbed back and forth between Beijing and Washington, with the occasional involvement of Brussels, Canberra or other Western capitals.

But the problem is compounded by very different perceptions of the political risk of doing business in China or with China, speakers said at this week's Reuters China Investment Summit.

China feels aggrieved when its firms are blocked from buying or investing in foreign counterparts, perhaps most notably in 2005 when US political opposition blocked CNOOC Ltd.'s $18.5 billion bid for oil company Unocal.

Westerners are likewise miffed when their bids for Chinese companies go astray, such as China's blocking of a planned Coca-Cola Co. $2.4 billion acquisition of top Chinese juice maker Huiyuan in March.

''People were a little bit surprised by the Coke/Huiyuan decision. People on the ground in China understand some of the constraints that the government was operating under in terms of public opinion,'' said Philip Partnow, deputy head of investment banking at UBS Securities Co. Ltd. in Beijing.

''But from a pure Western analytical perspective, people would look at it and say 'there doesn't seem to be a very good technical, fundamental basis for that decision, and so I have to assume it's a bit of local protectionism or whatever you want to call it – political protectionism – rearing its head'.

''I think that's the perception overseas.''

In a sign of further uncertainty over doing business in China, a reported government warning over defaults on derivative details with Chinese state-owned enterprises (SOEs) triggered anger and dismay over the possibility of defaults on commodity imports. Still, Larry Chen, chief representative of Bank of New York Mellon's Beijing office, said they remained optimistic about opportunities in China.

''We believe there is going to be further opening-up of the market in the next two to three years,'' he said.

China, though, feels that it is more often the victim, despite the fact that smaller and lower-profile deals sought by its companies are proceeding across the world.

This year, miner Rio Tinto rejected a $19.5 billion equity tie-up with Chinese metals conglomerate Chinalco, prompting state news agency Xinhua to slam Rio's ''perfidy'', saying the deal fell apart due to ''possible political prejudice.''

''Foreigners reject Chinese projects more than China rejects foreign projects,'' said Yang Junmin, vice general manager of Beijing Sinodrill Co., which specializes in minerals exploration.

''China is an open country, and open trade is a win-win for both sides. I think that if you try to restrain a country, all you're really doing is restraining yourself,'' he added.

For Chen Dongqi, an economist with a government think-tank, US rejection of Chinese or other foreign acquisition or investment bids – often on security grounds – is foolish.

''I think the United States is too narrow-minded, at least, they lack an understanding of the broader picture,'' Chen said.

Washington was only interested in letting in Chinese money as a last resort, such as during the current financial crisis, he said.

''As a Chinese scholar, I don't think they can talk about fairness and freedom as they're not fair to us,'' Chen said. But the issue on many investors' radar screens recently is China's arrest of four Rio Tinto employees on suspicion of bribery.

''I don't think that's caused people to not want to evaluate or negotiate transactions. I don't see that. I do think Chinese SOE employees are getting much more careful about what they are or are not able to tell outsiders,'' said UBS's Partnow.

''There have been numerous times when we've been in meetings with clients where they're even concerned about giving you their personal speculation,'' he added.

''It's very common when people get together around a certain industry to talk shop a little bit, but people who six months ago you would normally have had informal chit-chat with are now all of a sudden saying 'it's not that convenient to talk'.''