BUSINESSES which want to be in the most dynamic economies in Asia should choose Hong Kong, China or Singapore, according to a report by the Political & Economic Risk Consultancy (PERC). They should stay away from the Philippines and consider switching out of the slowing economies of Japan, South Korea and Taiwan. If sleeping at night is the main criterion, then it is Singapore and Hong Kong, which offer the lowest socio-political risk, but beware . . . the territory's ranking is falling, according to the PERC report. The survey warns that China's dynamism comes with the greatest risk of inflation in the region, and the most volatile currency movements. With real gross domestic product growth averaging 12.9 per cent for last year and this year, and forecast of 9.5 per cent next year and in 1995, China continues to lead the Asian economies in the growth league, followed by Malaysia and Thailand. Hong Kong ranks just fifth in PERC's calculations. The territory is regarded as a poor risk in terms of inflation control, falling in just behind the most risky - China. Best inflation fighters are reckoned to be Japan and Singapore. To avoid currency risk, avoid Japan, says PERC. Over the next two years the yen is judged to be liable to swing around more than any other currency in the region, although the Philippines is not far behind. Despite the question marks over plans for the convertibility of the yuan, China is put in the middle rankings of currency risk, while Hong Kong, thanks to its peg to the US dollar, gets top billing. As well as assessing the vital signs of the economy, PERC correspondents have also taken soundings of the social risks which loom over the region. Not surprisingly, given South Korea's robust approach to politics, the militancy of its workforce, and the readiness of the populace to take to the streets whenever they have a grievance, the country is ranked most likely to deteriorate. But despite the lingering smell of tear-gas, South Korea's potential for social unrest has fallen considerably over the past year, says PERC. The future depends on the big wild card - North Korea. The graph for Taiwan is going up because of politics and the divisions between independents and the traditional line of the ruling Kuomintang party. Taiwan is also at risk from stock market scandals, development outrages, as well as regulatory changes which could affect special interest groups. Chauvinism which could manifest itself as negative discrimination is more likely in South Korea than anywhere else in Asia. ''The psychology of self-sufficiency makes it difficult for foreigners to break into the Korean market. Koreans have the irritating habit of treating almost every endeavour as if national pride were at stake,'' PERC says. China once presented the worst risks of nationalism to outsiders, but is now more moderate in the name of economic development. For lack of discrimination against outside concerns, Hong Kong and Singapore are the most welcoming, but the Philippines is becoming less intimidating as it becomes keener to attract foreign investment. The prize for the ever open hand goes to China. It shares a reputation for corruption, being beaten in the bribery stakes only by the Philippines and Thailand. For lack of value for money, the Philippines is extremely high risk, warns PERC. ''In Indonesia, a person at least usually gets what he pays for, whereas in the Philippines, a businessman often pays and still comes away empty-handed.'' For corporate cleanliness, the prize goes to Singapore. Hong Kong comes a close second and is by far the least bureaucratic economy in the region. ''Hong Kong is allergic to bureaucracy,'' says the report, adding that it is less intrusive than in every other country in Asia, and most in the world. This might change in the run-up to 1997, but there is no sign of this threat having materialised yet, say analysts.