Supporting reporter M. A. Farber and The New York Times, New Jersey Attorney General John J. Degnan urged the Supreme Court yesterday to decide whether freedom of the press must be balanced against the right to a fair trial when materials are subpoenaed from news organizations.

The plea reached the court while it is weighing a decision on whether Farber must return to the Bergen County Jail, where he has served 27 days for contempt of court for refusing to turn over his files on a series of deaths at a Oradell, N.J., hospital in the mid-1960s.

Dr. Mario E. Jascalevich, who is on trial for murdering several of the patients, subpoenaed the file.

Farber is free on an indefite stay granted by Justice Potter Stewart Sept. 26.

In a preliminary brief on the eve of the justices' closed conferences. Degnan urged them to determine not only if there should be a balancing of the rights guaranteed by the First and Sixth amendments to the constitution, but also to determine "the consitutional nature of the 'balancing test' to be applied."

Farber and the Times made a similar request in a petition for review of a New Jersey Supreme Court ruling that there isn't any First Amendment interest to put on the scales against a subpoena for production of confidential press materials.

Degnan recalled that he has argued previously that it was improper for the trial judge to have issued "an apparently all-inclusive subpoena" so that he could examine Farber's filed in chambers, without first requiring Jascalevich to demonstrate at a hearing that the file was relevant material and necessary to the defense.

At the heart of the issue is a 5-to-4 U.S. Supreme Court decision in a 1972 press case. Justice Lewis F. Powell Jr., in a separate opinion agreeing with the majority, wrote that trial courts, "in considering a motion to quash a subpoena directed to a newsman . . . should balance the competing values of a free press and the social interest in detecting and prosecuting crime."

Yet, Degnan pointed out, the New Jersey Supreme Court majority "Held the while a 'balancing test' was required in future cases" where the state reporters' shield law might be invoked the First Amendment afforded Farber and the Times no protection.

Supporting a petition for high court review, Degnan said that clarification of the 1972 ruling "would be appropriate in light of the conflict among lower state and federal courts with respect to whether a 'balancing test' is required . . ."

Jascalevich is accused of killing three patients with a muscle-relaxing drug. The trial, almost complete, has been suspended, but is scheduled to resume Tuesday.

The Supreme Court returns the same day. It has before it an application by Jascalevich, opposed by Farber and the Times, to lift the stay of the reporter's jailing for contempt.