'IMF get out'
Some protesters, many shouting "IMF get out!", attempted to break through police lines and march to a complex where the IMF and World Bank were wrapping up discussions on internal reforms and the fragile recovery from the global economic meltdown.
At least 20 demonstrators were arrested.
Similar scenes were witnessed on Tuesday when the meetings began, with police detaining about 100 people.
Quoting trade union officials, Anita McNaught, Al Jazeera's correspondent in Istanbul, said: "IMF and World Bank policies mean hunger, poverty and unemployment for ordinary Turks.
"Everyone here knows that there is a huge immediate and future cost in allowing unemployment figures to remain high.
"Many protesters feel that they [IMF and World Bank] have kept Turkey looking stable - with fiscal track records acceptable to foreign investors and foreign governments - but the price the people of Turkey have paid has been far too high."
An estimated 13,000 people are attending the two-day event featuring finance ministers, central bankers and academics from the member states.
Governments and big business are looking to the two 186-member financial institutions to help bolster a tentative recovery and mitigate the social effects that the economic crisis is having.
Speaking to Al Jazeera from Istanbul, Ngozi Okonjo-Iweala, the managing director of the World Bank, said that developing countries needed to be included in any solution to the economic downturn.
Okonjo-Iweala said: "We had both after the G20 and after the meetings here a strong endorsement of the need to integrate developing countries, and especially low-income countries, into the solution for the global crisis.
"There is a recognition to support them to have their own fiscal stimulus.
"The work that the World Bank has already done in directing about $58.8bn in resources to these countries has been strongly supported here, with $14bn going to the lowest-income countries.
"In Africa, for example, you have almost one billion consumers, whom if they [donors] invested in, can also form part of the global solution."
|An estimated 13,000 people are attending the two-day event [AFP]
Reflecting economic fears, finance chiefs have sounded a cautious note at the meeting.
Robert Zoellick, the World Bank president, said: "There are many risks out there. These include growing unemployment lines, rising protectionism and still-large output gaps.
"The global economy could still suffer a setback, not least in 2010 when governments plan to withdraw much of their economic stimulus and debt rollovers could be combined with a rise in interest rates."
Dominique Strauss-Kahn, the IMF chief, sounded a similar note.
"There is no way to say the crisis is over when we still have this big rise in unemployment in front of us," he said.
The IMF and World Bank are also looking beyond the crisis at ways of managing a global economic system in a way that will make it less prone to downturns and at a world where US consumer spending will no longer play such a dominant role.
World leaders of the Group of 20 (G20) major developed and emerging economies last month entrusted the IMF with monitoring economic and financial stability around the world in order to help spot problems early.
Developing nations are also to be given greater voting rights in both the IMF and World Bank under complex reforms that are still being thrashed out as emerging economies such as Brazil, China and India lobby for a bigger role.