The ethics panel for federal judges said yesterday that seminars in Florida attended at the expense of large corporations by more than a hundred federal judges may be improper.

The ethics committee of the Judicial Conference, which administers the federal judiciary, suggested that judges not attend such seminars if the corporations providing the money or are likely to be involved in cases before them and if the seminar concerns subjects related to those cases.

The seminars, sponsored by the Center for Law and Economics at the University of Miami, are financed by dozens of major corporations, including ITT, Exxon, General Motors and others. Collectively, they are annually involved in hundreds of court cases, especially antitrust and regulatory cases. The seminars cover the economics of antitrust and regulation among other subjects.

The seminars were publicized last year after lawyers and law school professors, most of them advocates of vigorous government regulation of private industry, complained to newspapers and legal publications that the judges were being "brainwashed" and "lobbied" at these seminars. The seminar sponsors and the judges who have attended -- about a fifth of the federal judiciary -- deny the charges.

The advisory opinion issued yesterday by the conference committee on codes of conduct did not specifically mention the Florida seminars. But its opinion was prompted by an inquiry about them, one of two filed recently.

The opinion said acceptance of such trips constituted a gift that must be disclosed on fianncial disclosure statements. Attendance "would be improper . . . if the sponsor or the source of funding is involved in litigation or likely to be so involved and the topics covered in the seminar are likely to be in some manner related to the subject matter of such litigation."

Howard T. Markey, the chief judge of the U.S. Court of Customs and Patent Appeals and chairman of the advisory committee, said through a spokesman that it is up to each individual judge to interpret the opinion, which does not constitute an order.