NEW YORK (Reuters) - Robert Willumstad, the newly installed chief executive at American International Group Inc , and Maurice (Hank) Greenberg, who ran the insurer for nearly four decades, are set to meet tomorrow.

Willumstad, who was named CEO of the world's largest insurer on Sunday, earlier this week said he wanted to meet with Greenberg to forge a more "interactive" relationship. A spokesman for Greenberg said the two had agreed to meet on Thursday.

Greenberg, who quit AIG three years ago amid an accounting scandal but remains a large shareholder, has in recent months been scathing in his criticism of management at his former company, as it racked up record losses from bad mortgage bets. There is also a string of lawsuits outstanding between the two sides. In an earlier interview with Reuters, Greenberg said he had not been back to AIG's New York headquarters near Wall St. since leaving the firm, calling it a "hostile" environment.

But the meeting this week with Willumstad, who replaced Greenberg's successor Martin Sullivan as CEO, is seen as a step toward addressing Greenberg's grievances, and beginning to heal the rift. Greenberg's spokesman said the meeting would not be at AIG's offices.

Greenberg controls more than 12 percent of AIG shares through a personal stake, family trusts and control of companies that are AIG's largest shareholders.