The presiding judge in a 12-year-old government antitrust trial against International Business Machines Corp, today told both sides they should finish their arguments by June 1.

U.S. District Court Judge David Edelstein also told attorneys for both the federal government and IBM that they should try to reach a settlement and said he would be willing to assist in negotiations between the Justice Department and the world's largest computer company.

"So I say, and I offer this," Edelstein said at a hearing this morning. "If you wish to go back to the Department of Justice and if [IBM attorney Thomas] Barr consents, here is my invitation: I offer my services to participants in the settlement discussion. I will come to Washington as often as I have to. Maybe we can sort of use Washington and New York. I will do whatever I can do in order to produce a settlement of this case."

In early 1969, the Justice Department sued International Business Machines, alleging that through its sales practices and other means sought to monopolize the computer industry in the United States.

After six years of depositions, document search and motions, the case finally came to trial in 1975. Edelstein said today that, unless there is a compelling reason of "justice," both sides should conclude the trial by June 1. Unless there is a settlement, Edelstein will have to render a decision on the basis of six years' testimony and hundreds of thousands of pages of documents.

Trial sources said that a settlement, if one can be reached, is in the interest of the court, IBM and the government. The government can get some of the "relief" it seeks, IBM can insure that it is not subject to private interest antitrust suits (which it probably would face if the verdict is unfavorable), and the judge can bring the trial to a conclusion without the appeals and other litigation that would ensue.

Edelstein said that he could be a useful go-between in settlement negotiations both because he knows the facts of the case so well (he has presided over the case for the full 12 years) and because if there are hearings on the settlement, they will have to come before him.