Some of the nation's top corporate leaders today expressed both suprise and doubt over reports that the Federal Reserve Board had changed policy in an attempt to force interest rates down.

Gathered here for the semiannual meeting of the Business Council, a group of nearly 200 of the nation's biggest corporations, most of the chief executives said they had no firsthand information on the matter and therefore would have no comment. But some, such as Citicorp Chairman Walter B. Wriston, said they doubted the reports.

"I would seriously doubt that the Fed would change it," said Wriston, who also is chairman of the Business Council.

Charles L. Brown, the council's vice chairman and chairman of AT&T, said he knows of no change in the central bank's policy and, therefore, declined further comment.

A policy change might cause forecasters to lower their projections for interest rates in 1983, said W. Reid Thompson, chairman of Potomac Electric Power Co. "It would lower my view" of interest rates, Thompson added.

Federal Reserve Chairman Paul Volcker is scheduled to address members of the Business Council in a closed session on Saturday and may shed some light on the situation.

The Washington Post reported Friday that the Fed's Federal Open Market Committee had voted on Tuesday to ease credit by essentially abandoning--at least temporarily--the monetary policy it adopted on Oct. 6, 1979. Under that approach, the Fed would try to control the money supply while allowing the marketplace to determine interest rates.

Last week, however, after receiving an exceptionally gloomy forecast for the economy over the next six months, sources said the Fed voted to ease credit and adopt an approach of more direct control over interest rates in an effort to stimulate the economy.

Martin Feldstein, President Reagan's nominee to head the Council of Economic Advisers, also expressed doubt that the Fed had changed policy. After appearing before the Business Council, Feldstein said, "I see no basic change in the Fed's policy. I don't think that you can read from the statistics that the Fed has changed course. I don't know who is leaking what kind of speculation or why they are leaking it."

Feldstein noted that the Fed has been "winning the battle of changing people's expectations" and that "they feel it is very important to stay on the course that was set back in 1979."

Although acknowledging the existance of much uncertainty by consumers about the economy, Feldstein noted that declining interest rates and improvement in the bond market indicate that inflation is under control. But, he added, "The implication that falling interest rates will somehow be the result of Fed easing, I think, does not follow. It could be just be the opposite way."