SINGAPORE: Asian shares tumbled on Monday after the U.S. Federal Reserve's decision to keep interest rates at record lows raised fresh concerns about growth globally, particularly inChina.

MSCI's broadest index of Asia-Pacific shares outside Japan .MIAPJ0000PUS fell 2 percent, with Australia AXJO down 2.4 percent and South Korea .KS11 off 1.7 percent. Japan was closed for a long holiday.

Both the Shanghai Composite index .SSEC and the CSI300 .CSI300 were little changed.

Investors will be focussing on flash manufacturing activity readings from China and the eurozone on Wednesday.

A Reuters poll showed economists expect the flash September China factory PMI headline reading to edge up to 47.5 from 47.1 in August.

But it likely remained near 6/1-2-year lows, pointing to a seventh straight contraction in activity on a monthly basis.

"It looks like a continuation of the growth worries that have hampered markets for the last few months now," said Shane Oliver, head of investment strategy at AMP Capital in Sydney.

"European and U.S. shares had sharp falls, after initially benign reactions to the Fed, and this is now flowing through to Asian markets today," he said.

U.S. shares dropped more than 1.3 percent on Friday, after Fed Chair Janet Yellen said on Thursday that the global economic outlook appeared less certain.

U.S. and European debt yields also tumbled, with the policy-sensitive two-year yield US2YT=RR falling to 0.678 after hitting a four-and-a-half year high of 0.819 percent earlier in the week.

The 10-year German Bund yield EU10YT=RR fell 12 basis points to 66 basis points, its biggest one-day drop since early July.

"The monetary-policy-watcher world has now turned decidedly bearish" after the Fed meeting, Evan Lucas, market strategist at trading services provider IG in Melbourne, wrote in a note.

"If emerging market risk, coupled with low-growth European environment is affecting Fed decision making, sentiment uncertainty will amplify," he said.

The U.S. dollar, which retreated after the Fed decision, rose 0.3 percent to 95.135 against a basket of six currencies .DXY but slipped 0.2 percent to 119.79 yen on Monday.