A House subcommittee chairman yesterday accused the American Medical Association of "willful and contemptuous action" and refused to allow the AMA to deliver scheduled testimony on unnecessary surgery.

The AMA said the charge was based on misunderstanding.

Chairman John E. Moss (D-Calif.) of the House Commerce Oversight and Investigations subcommittee deffered the AMA testimony until Monday because, he said, the organization failed to deliver advance copies "in timely fashion."

Copies of the testimony by AMA Executive Vice President Dr. James Sammons were given to a reporter and the committee staff late Friday, Moss said. He charged that the reporter got the testimony first.

Moss and the AMA have been at odds since the subcommittee said in a report last year that doctors performed about 2.38 million unnecessary observations in 1974, resulting in 11,900 deaths at a cost to the public of nearly $4 billion.

In the prepared testimony, Sammons had planned to restate the association's "sharp disagreement" with the subcommittee report.

"I cannot help but note that this is not the first act of such obvious discourtesy shown by the AMA." Moss said in a statement read yesterday by Rep. Henry A. Waxman (D-Calif.). Moss, according to staff aides, was shaken up in an automobile accident over the weekend.

An AMA legal officer tried to respond to the charges as the hearing begun but was refused by Waxman.

In a statement distributed to reporters, the AMA said: "We regret that this incident occured." The AMA also said the subcommittee staff had agreed that advance copies of the testimony could be given out Friday.

Sammons' prepared testimony urged that subcommittee to reject the theory that the benefits of a hysterectomy for the purpose of cancer prevention are insufficient to justify the

"I cannot believe that a subcommit-cost.

lee of the Congress of the United States is going to tell the women of this country they cannot or should not have an operation that could avoid the agony and ultimate death by cancer because, according to some abstract formula, it is not 'cost effective' and therefore unnecessary," the advance copy said.

The AMA called the subcommittee's research "unsound . . . unscientific."