Police said one person died during the protest. The man was found in a street near the central bank where he had fallen down and stopped breathing at around 7:30 p.m. (2:30 p.m. EDT), they said.
It was not immediately clear what caused the man's death and a police source said he likely died from a medical condition, although that would not be confirmed until after a post-mortem.
More protests were planned for Thursday, the main day of a summit involving the world's biggest economies, developed and up-and-coming, in all accounting for more than 80 percent of world trade and economic output.
Global economic output is expected to contract more in 2009 than any year since World War Two, dropping between 0.5 and 1.0 percent, according to the International Monetary Fund, whose head, Dominique Strauss-Kahn, is calling it a "Great Recession."
The International Labour Organization says the crisis could cost 50 million jobs by the end of the year.
G20 leaders were preparing a major expansion in resources available through the IMF, possibly including a tripling of its war chest to $750 billion, officials familiar with negotiation of the issue said.
The draft communique contained a pledge by the G20 nations to allow "candid, even-handed and independent" surveillance of their economies and financial sectors by the IMF.
It also unveiled a Financial Stability Board to work with the IMF to identify economic and financial risks and measures needed to address them, revamping an existing body called the Financial Stability Forum.
MOBILISING TRILLIONS
The G20 leaders hope around two trillion dollars governments are pumping into the economy in tax cuts, building projects and green investments, according to summit host Gordon Brown, will limit the depth and duration of recession and maybe create 20 million or so new jobs.

Black Friday 2009 deals are everywhere online and now Apple has jumped onto the ...
A team of unidentified hackers has managed to steal "confidential" global warming data after breaking into the e-mail server of a prominent, Brit...


Online distributor for point of sale equipment, TYSSO and Pegasus.