Talks on "Plan B" have emerged because patience has run out with the US Congress' failure to ratify the 2010 reforms originally strongly supported by the White House.
The reforms would both realign the power of members on the IMF executive board, boosting emerging countries like China and India, and double the capital resources the bank uses to support countries in financial crisis.
Brazil's executive director at the IMF, Paulo Nogueira Batista, has outlined a plan to "delink" the two components of the reforms in a way that could allow them to go ahead without requiring the US Congress to approve them.
"The delinking proposal is constructive and simple and could clear the way for the continuation of the IMF reform process."
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The Brazilian plan would first advance the modest realignment of power as planned since 2010 by giving emerging countries more seats on the executive board at the cost of Europe.
That proposal was long-accepted by the White House, but blocked by Congress.
That could challenge Washington's dominant role in the Fund since it was established in 1945.
Because contributions to IMF resources determine a country's voting quota, if Congress still does not give its support, its quota could fall from 17.7 percent to 9.8 percent, according to Batista's plan.
That drop is significant because major IMF board decisions require 85 percent of quotas in support, giving the United States unique veto power.
Batista allows that a deal could be done to allow Congress time to reconsider and endorse the resource increase, restoring Washington's veto.