The Reagan administration may refrain from asking the Senate to ratify new provisions to the Geneva conventions on protection of war victims, fearing the revisions would provide a safety net for terrorists, officials said yesterday.

The revisions, adopted by a conference sponsored by the International Committee for the Red Cross in 1977 and signed by more than 100 nations, were designed to improve treatment of combatants and civilians during war.

But senior U.S. military and defense officials said the revisions effectively legitimize national liberation movements and terrorists, conferring on them the status of combatants qualified to engage in hostilities and enjoy the protections of prisoners of war, including exemption from criminal prosecution.

The Joint Chiefs of Staff have notified Defense Secretary Caspar W. Weinberger of their opposition to the revisions, and International Red Cross officials have been told the administration has "grave problems" with the changes, U.S. officials said.

Deputy Assistant Defense Secretary Douglas J. Feith, reflecting the military's objections in an academic paper delivered last spring, called the conference a "truly malign perverseness" and the revisions an endorsement of "both the rhetoric and the anticivilian practices of terrorist organizations that fly the banner of self-determination."

The revisions, known legally as protocols, were signed by the Carter administration in 1977, although they were to be analyzed by the Joint Chiefs before submission to the Senate for ratification.

White House spokesman Larry Speakes, responding to a report in yesterday's editions of The New York Times, said, "There are problems with these protocols, one of which is equating national wars of liberation with belligerent status. Accordingly, under this, a terrorist could be given belligerent status under international law."

The Geneva conventions of 1949 restricted combatant status to national armies and "irregular" forces who wear uniforms, carry arms openly in all military operations and comply with the laws of war.

But protocols drafted by the three-year conference expanded the definition to include "peoples" who "are fighting against colonial domination and alien occupation and against racist regimes in exercise of their right of self-determination."

Regional political organizations are given authority by the protocols to judge who qualifies as a combatant. The Arab League, for example, would be able to decide whether the Palestine Liberation Organization qualifies.

U.S. critics argue the protocols, if observed by Israel, could allow a terrorist deemed a legal combatant by the Arab League to bomb civilian targets in Israel and escape criminal prosecution if captured.

New criteria for judging combatants also trouble administration officials. The protocols, diluting the Geneva accord's so-called "openness" requirement regarding arms and uniforms, note that "owing to the nature of hostilities an armed combatant cannot so distinguish himself."

In such circumstances, the combatant must carry arms "openly during each military engagement" that is an actual attack or during "military deployment."

Critics contend that the phrase "military deployment" is so vague that a government that captures a terrorist in its territory concealing a bomb would be required to grant him prisoner-of-war status unless it could prove he was deploying it.

Officials are trying to determine whether the document can be salvaged by having the United States reserve the right to reject the provisions for certain groups.

But Pentagon officials and the Joint Chiefs believe the protocol is fundamentally flawed and would have little legal significance if amended, according to officials.

Feith, the Defense Department official handling the issue, said in a paper delivered in April to a conference at the Fletcher School of Law and Diplomacy that the protocols flout humanitarian law designed to protect civilians from combatants by clearly distinguishing between the two.