* China Sept PMI contracts more sharply than expected
* Bonds supported by weak economic outlook
* Aussie comes under pressure, U.S. dollar strong
* Sentiment at Asia's biggest firms sour - survey
* Copper extends big overnight losses
By Saikat Chatterjee
HONG KONG, Sept 23 (Reuters) - Asian stocks looked set for their biggest single-day fall in a month on Wednesday after factory activity in China shrank more than expected, adding to fears of a weakening global economy and sending investors into safer assets such as government bonds.
Financial spreadbetters predicted European markets would follow Asia lower, with Britain's FTSE 100 seen opening down 0.9 percent, Germany's DAX 1 percent and France's CAC 40 0.7 percent.
S&P mini futures fell 1 percent after the weak China report, pointing to a weaker opening on Wall Street.
MSCI's broadest index of Asia-Pacific shares outside Japan fell 2.5 percent, its biggest daily loss since Aug. 24, according to Thomson Reuters data.
China's stocks were among the hardest hit in the region with main indexes down more than 2 percent. Australia fell 2 percent and South Korea shed 1.5 percent. Japanese markets are shut through Wednesday.
"The industrial sector in China remains a concern, indicating that the economy is not out of the woods yet, while the Fed's comments last week indicate a glass half-empty view of the global economy," said Tai Hui, chief Asia markets strategist at JP Morgan Asset Management in Hong Kong.
More evidence of a slowdown in the world's second-biggest economy was evident in the preliminary Caixin/Markit China Manufacturing Purchasing Managers' Index (PMI).
Activity in China's factory sector failed to improve in September as expected, and instead shrank for a seventh straight month to its weakest level in 6-1/2 years, the private survey showed.
The findings could add to fears that China's economy is cooling more sharply than earlier expected, though most analysts still believe a gradual albeit bumpy slowdown is more likely.
On Tuesday, the Asian Development Bank lowered its growth forecast for China to 6.8 percent for 2015.
Sentiment at Asia's biggest companies tumbled at a record pace in the third quarter on worries about China and the risks it poses to global growth, a Thomson Reuters/INSEAD survey showed.
Overnight on Wall Street, the Dow Jones industrial average fell 1.09 percent, the S&P 500 lost 1.23 percent, and the Nasdaq Composite fell 1.5 percent to 4,756.72.
Losses in equities prompted investors to plough funds into fixed-income assets. The benchmark two-year U.S. Treasury yield fell to 0.68 percent, nearing a two-week low.