CAMBRIDGE, MASS., NOV. 7 -- An unauthorized wiretap was found on the office telephone of a Harvard University professor instrumental in the defeat of Robert H. Bork's nomination to the Supreme Court, officials said today.

Prof. Laurence Tribe confirmed that his office phone line was tampered with, but He refused to speculate on the source of the plant.

"It's outrageous. Whoever did this obviously believes the ends justify the means," Tribe said. "I have no idea what the ends were, but the means were obviously reprehensible and somewhat frightening."

The wiretap was discovered Monday, after Tribe's secretaries reported hearing strange noises on several occasions. New England Telephone said the line was not placed by its representatives. Telephone company technicians brought in by Harvard found a "nonstandard telephone installation," company spokesman Mark Marchand said.

"All we know is that we checked it out and it is not a standard telephone installation," Marchand said. "It is something that is being investigated by the proper legal authorities."

Officials of the FBI and the state attorney general's office said they would look into the matter.

Daniel Steiner, Harvard vice president and general counsel, told The Boston Globe that telephone company officials, the university telecommunications department and an outside consultant agreed that the tap would only have been placed to monitor Tribe's phone calls.

Technicians estimated the connection had been in place from two to eight months, based on scratches and tarnishes on the device.

Tribe, the Ralph Tyler Jr. professor of constitutional law and a well-known liberal legal scholar, was a consultant to Sens. Edward M. Kennedy, (D-Mass.) and Joseph R. Biden Jr. (D-Del.) in their efforts to defeat Bork's nomination. He testified for three hours during hearings on the nomination.

Tribe also acted as counsel to Pennzoil in its $10.3 billion suit against Texaco. The dispute was settled in Pennzoil's favor last April, but aspects of the case continued into summer and fall.

He told the Globe he could remember only one incident in which information he revealed in private telephone conversations was apparently leaked to other parties -- the day before Judge Douglas H. Ginsburg, a former Harvard law professor, was nominated by President Reagan to the Supreme Court.

Tribe told the Globe he spoke to two friends in Washington, telling them that although he liked and respected Ginsburg, he had questions about Ginsburg's qualifications.

The next day -- a few hours before Ginsburg's nomination was announced -- Tribe said a colleague informed him, "It's all over Washington that you're trying to stop Doug Ginsburg's nomination."