NEW YORK (CNN/Money) - New York state Attorney General Eliot Spitzer is forming a multi-state task force to investigate possible securities fraud committed by brokerages.

Spitzer will co-chair the task force, to be formed with the North American Securities Administrators Associations (NASAA), which represents securities administrators in all 50 states, the District of Columbia, and Puerto Rico.

The move effectively widens Spitzer's investigation of New York-based brokerages for conflicts between the research and investment banking arms.

Last week Merrill Lynch agreed to Spitzer's request for further disclosure about banking relationships with companies covered by their analysts. The two sides are still negotiating about a possible monetary settlement and admission of wrongdoing.

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According to a statement, NASAA President Joseph Borg said the association will be "working with New York in the continuing investigation of other investment banking firms, which will center on practices that adversely affected thousands of Main Street investors nationwide."

On Wednesday Spitzer is scheduled to join U.S. Representatives Dick Gephardt, D-Mo., and John J. LaFalce, D-N.Y., at a press conference on Capitol Hill and is expected to criticize the Republican Corporate and Accounting Reform Bill.