Supreme Court Justice Thurgood Marshall offered a flicker of hope yesterday to The New York Times and reporter M. A. Farber in their fight against disclosure of investigative material at the "Dr. X" murder trial in New Jersey.

Farber, who had been scheduled to go to jail at noon yesterday for failing to obey a subpoena for his notes and other documents is now free until noon towmorrow because of Marshall's order. A $5,000-a-day fine against The Times also is delayed until that time.

Marshall extended for two days a temporary stay granted earlier and then vacated Tuesday by Justice Byron White. The Times and Farber are seeking a longer stay of the contempt judgment so the Supreme Court can rule on the free press issues involved in the case.

A $1,000 fine also was imposed on Farber, who was ordered by Superior Court Judge Theodore Trautwein to remain in jail until the material subpoenaed by the defense is produced at the trial of Dr. Mario Jascalevich in Hackensack, N.J.

The physician is charged with the murder of three patients of Oradell Hospital in Riverdell, N.J., where he was chief of surgery from 1965 to 1966. An investigative series by Farber led to the Doctor's indictment.

Trial Judge William Arnold wants to see the Times documents to determine whether the defense should have them.

At this stage of the case the Supreme Court must decide whether it will be accepted for full review, and the votes of four Justices are needed. White said he did not think for the court to take the case the votes could be mustered for review at this point. Marshall is pondering the same question.