New York Times reporter M.A. Farber was threatened yesterday with yet another court order to surrender his notes on a murder case.

He already has spent 27 days in jail for his refusal to turn over the documents. It was his defiance at Superior Court Judge William Arnold's first order that escalated into a test of reporters' rights to protect their sources vs. a defendant's right to a fair trial.

In a confusing end to Farber's first days as a witness in the murder trial of Dr. Mario Jascalevich, Arnold said he believes he has authority to again order Farber to surrender his notes although the New Jersey Supreme Court is considering Farber's appeal from his first order.

However, the judge - who issued his first order without holding a hearing on Farber's claim that New Jersey's shield law and the First Amendment give him a right to refuse - told Farber's lawyer Floyd Abrams that this time he will hold a hearing.

He set the hearing for 9 a.m. today pending a check he said he would make with the state Supreme Court "to make certain I'm not usurping their authority."

Arnold also asked Abrams and Jascalevich attorney Raymond A. Brown, who calls Farber's notes vital to his client's defense, whether the hearing should precede or follow another order by Arnold commanding Farber to turn over the documents.

The judge said he thinks he should issue another order first. Abrams disagreed, saying, "I would rather argue to you before you make up your mind."

Arnold agreed with Abrams' contention that the judge cannot send Farber to jail for refusing while the Supreme Court is considering the case, but he appeared to accelt Brown's argument that there is a distinction between Farber's earlier refusal to obey a defense subpoena and his refusal yesterday as a witness at the trial.

Until Brown asked Farber to turn over his material, the Times reporter had answered all of his questions yesterday. Farber did not evoke shield law or constitutional privilege when asked whether he had spoken with several of the doctors who worked at Riverdell Hospital in Oradell, N.J., with Jascalevich at the time of a series of mysterious deaths there in 1965-66.

Jascalevich's possible connection with the deaths was examined by but he appeared to accept Brown's arprosecutors in 1966, but the case was closed. It was reopened in 1975 by a different prosecutor, Joseph Woodcock Jr., after Farber had begun looking into the long-dormant mystery.

Woodcock has testified that he would not have reopened the case without the spur of Farber's reporting, including Farber's discovery of a deposition by Jascalevich that had been missing from the prosecutor's file.

Woodcock's reopened investigation led to the indictment of Jascalevich. He is accused of murdering three patients by injecting them with fatal doses of the muscle-relaxant curare. Jascalevich's trial is nearing the end of its seventh month.

After Farber first refused to turn over his notes for Judge Arnold to determine whether they should be given to Jascalevich's defense, another Superior Court judge, Theodore Trautwein, found Farber in contempt and ordered him jailed until he agreed to comply.

Trautwein also ordered The New York Times to pay a fine of $5,000 a day until Farber compiled.

The state supreme court ordered Farber's release and suspended the daily fines after 27 days while it undertook consideration of Farber's appeal. The Supreme Court held a hearing two weeks ago, but has not ruled.

Before the new controversy over Farber's notes erupted yesterday, Farber testified that he had talked with Jascalevich's principal accuser, Dr. Stanley Harris. Under examination by Brown, Farber said that he does not recall whether or not he possesses notes of what Harris told him.

Farber has argued that the subpoena seeking all his notes is too broad, but he has said that, if the subpoena is made more specific, he is willing to turn over some information from his files that does not violate pledges of confidentiality he gave to sources.

Defense attorney Brown argued yesterday that because Farber was given access to the prosecutor's file and was crucial to reopening the case, he was acting as an arm of the prosecution and therefore waived his reporter's right to protect sources.