U.S. District Judge Harold Greene said yesterday the government's antitrust case against American Telephone & Telegraph Co. has been "respectable" and refused to hear AT&T arguments now that the case be dismissed.

Greene's comments came as the government neared the close of its four-month-long presentation of evidence in the landmark antitrust suit in which the Justice Department is seeking a breakup of AT&T.

"Whatever the substantive merits of the motions, and the case generally, will ultimately turn out to be, I don't believe the government's evidence justifies such cavalier treatment," Greene said. "The government has presented a respectable case that the defendants have violated the antitrust laws."

Green also rejected AT&T arguments that he should make a speedy decision on continuing the case, since some members of the Reagan administration have recommended that it be dropped. "I haven't heard from the government that they are concerned," Green said. "In any event, I don't propose to act on the basis of press reports or someone's concern unrelated to this lawsuit.

"The court has an obligation to deal with this lawsuit under existing antitrust laws, and it will do so irrespective of speculation or consideration outside the judicial arena," Greene said.

AT&T lawyers have said they plan to seek dismissal of the suit or a narrowing of the issues in the case when the government closes its presentation, which is expected next week. Greene said such motions should be filed by July 10 and the government should respond by Aug. 7. Greene said he would hear oral arguments on those motions "almost immediately thereafter."

"After seven years of pretrial and four months of trial, there is no basis or need to decide these questions without normal briefing and arguments," Greene said.