China's economic expansion slowed in the third quarter to its weakest pace since early 2009 as euro-debt strains and a sluggish U.S. economy took a toll, but healthy domestic drivers suggest little room to relax monetary policy near term.

GDP grew 9.1 percent from a year earlier, the third consecutive quarterly slowdown in growth after 9.5 percent in the second quarter and 9.7 percent in the first.

But other figures on Tuesday suggested the domestic economy was growing healthily. Fixed-asset investment, the main driver of growth in world's second-biggest economy, and retail sales were stronger than expected.

That domestic strength and inflation of more than 6 percent argue for the central bank to keep a tight rein on monetary policy even though overall growth is slowing.

GDP growth was surprising for the market on the downside, said Stephen Green, economist at Standard Chartered in Hong Kong. There is clearer deceleration in the third quarter. No change in policy. Small signs of ad-hoc loosening but no macro change in policy.

Asia stocks eased and some commodity prices fell after the growth data, which was slightly below forecasts of 9.2 percent and the weakest since 8.1 percent in the second quarter of 2009.

Most analysts said the data pointed to an economic soft landing, rather than a crash. But the economy would be at risk of a more severe downturn if the euro-zone debt crisis and the U.S. economy lead to another global recession.

At the weekend, the G20 group of leading nations urged euro-zone leaders to resolve the debt crisis, which they said was endangering the world economy.

As an indicator of global demand, exports from China actually detracted from the economy's growth in the first three quarters of this year. That was underlined by September data showing exports growth to the euro zone, its biggest market, more than halved from August.

Still, China has plenty of firepower to direct at supporting growth if necessary, making a hard landing still an unlikely outcome, said George Worthington, chief economist for the Asia Pacific at IFR Markets, a Thomson Reuters unit.

Countering the impact of the global slowdown, fixed-asset investment in the first three quarters of the year chalked up annual growth of 24.9 percent, slightly ahead of forecasts of 24.8 percent.

Retail sales rose 17.7 percent in September from a year earlier, topping forecasts for a rise of 17.0 percent.

Indeed, industrial output in September rose 13.8 percent, above forecasts for an increase of 13.3 percent, suggesting the third quarter ended on a slightly upbeat note.

However, China's real estate investment, which accounts for a fifth of the country's fixed-asset investment, cooled sharply to 25.0 percent in September from a year earlier, as compared with a rise of 31.6 percent in August, Reuters calculations show, based on the official data.

Although economic growth has moderated slightly, it's still stable, Sheng Laiyun, spokesman at the National Bureau of Statistics, told reporters after the data release, dismissing the risk of a sharp deterioration in the economy.

It is more likely that China will keep its stable and relatively fast economic growth in the next phase, he said when asked about the possibility of a dip in growth.

INVESTORS EYE RISKS AS GROWTH EASES

Investors were a little less sanguine in their initial reaction. Hong Kong's benchmark Hang Seng Index <.HSI> extended early declines, dropping by as much as 3.7 percent.

Shares in Australian miners fell on the prospect that China's demand growth for minerals is easing. Rio Tinto fell 5.3 percent and BHP Billiton dropped 3.3 percent.

The slowdown weighed on sentiment in the oil and copper markets. Reuters calculations suggest implied oil demand in China rose just 1 percent in September from a year earlier, its slowest rate of growth so far this year.

China's Statistics Bureau said the economy was facing increasing uncertainty at home and abroad and it called for the maintenance of stable economic policies.

Slower activity could help some of that stabilisation process as it implies some softening of price pressures for inflation-wary officials in Beijing.

China's inflation, albeit easing, ran at an annual pace of 6.1 percent in September, within earshot of near three-year highs of 6.5 percent in July and well over Beijing's 2011 official target of 4 percent.

To combat rising prices and prevent them from stoking social unrest, Beijing raised interest rates five times and banks' reserve requirements nine times in the past year.

CONTROLLING INFLATION

Measures to curb inflation have had a noticeable effect and price pressures should ease further in the fourth quarter of the year, the Statistics Bureau said.

Housing inflation eased to the lowest level this year in September as Beijing's tightening measures, including rationed bank credit and rising mortgage rates, began to bite.

The darkening world economic outlook has forced Beijing to stand pat on policy since July. It has shown some concern about the economy, announcing measures to support small firms and intervening in the stock market to prop up bank shares.

Some analysts expect authorities to loosen policy a shade to support growth if need be. They may opt to ease credit controls or even cut banks' reserve requirements from record highs.

China has overtightened its policy since May. That has increased the risks of a hard landing, as global economic growth also slowed since the second quarter, said Dong Xian'An, chief economist at Peking First Advisory.

That risk of sharp economic slowdown in China still exists. We expect Chinese economic growth to slow down to around 8.6 percent in the fourth quarter, Dong added.

Brazil, Indonesia and Singapore have all eased policy because of concerns about the global economy. But few believe China is set to cut rates anytime soon given stubborn price pressures.

I don't think they will make any move (in rates) in the near term. Then maybe after a few quarters, toward the middle of next year, if everything is OK, I think they will continue to hike interest rates, not cut interest rates, said Ting Lu, economist at Bank of America-Merrill Lynch in Hong Kong.

(Editing by Ken Wills and Neil Fullick)