Philip B. Heymann, who headed the Justice Department's criminal division during the Abscam investigation, yesterday defended the government's tactics in the controversial case, saying there should be "no special rules for members of Congress."

Heymann, now a Harvard Law School professor, conceded that the investigation involved "absolutely incredible problems of management" including the fact that much of it was run through con men who could not always be relied upon.

Testifying before a House Judiciary subcommittee, he said, "Things could have been done better and should be done better in the future," but he said the problems were not serious enough to warrant throwing out the convictions of politicians who accepted bribes.

Abscam was the name given the sting operation in which FBI agents posed as aides to a phony Arab sheik attempting to trade bribes for legislative favors.

Six House members and one senator, as well as a number of lower level officials, were convicted. But the conviction of former representative Richard Kelly (R-Fla.) was vacated last month by U.S. District Court Judge William B. Bryant who found Kelly's right to due process had been violated.

Heymann said yesterday he believes Bryant's decision will be overturned on appeal.

Although Heymann was not involved in the day-to-day operation of Abscam, he made the decisions on which persons should be indicted.

The government has been criticized on the Abscam case for approving bribe offers to members of Congress who had no prior criminal history and whose reputations were damaged even though they did not take the money and were not indicted.

"Don't you agree this has a totalitarian smack to it?" asked Rep. Don Edwards (D-Calif.), chairman of the subcommittee on civil and constitutional rights.

Heymann said that there was a decision to run Abscam like any other undercover investigation and to avoid special rules just because important and prominent people were involved.

"No one felt they were out testing the corruptibility of congressmen or senators. The sense was that the bureau was discovering what were the practices among a handful of corrupt politicians," Heymann said.

Heymann said undercover operations are especially necessary in dealing with a member of Congress "for there is out there surrounding the Congress a world full of foreign representatives and private parties ready and willing to offer bribes to protect their vast stakes in what the Congress does."