SANTA BARBARA, CALIF., SEPT. 3 -- The White House today sought to avoid or at least delay a battle with Senate Armed Services Committee Chairman Sam Nunn (D-Ga.) that could hamper ratification of a pending U.S.-Soviet treaty to scrap intermediate- and short-range nuclear missiles in Europe and Asia.

In a letter released Wednesday, Nunn told President Reagan that he would hold up ratification of the proposed treaty unless the administration backs away from a broad interpretation of the 1972 Antiballistic Missile (ABM) Treaty. The broad interpretation, opposed by Nunn and some of the arms-control experts who negotiated the ABM treaty, would permit development of the administration's space-based missile-defense program, the Strategic Defense Initiative (SDI).

Nunn, saying that he hopes to avoid a future dispute over the meaning of the proposed treaty on intermediate-range nuclear forces (INF), said he would delay ratification unless the administration provides a complete record of the six years of negotiations on it.

Deputy White House spokesman Dan Howard said today that the administration is studying Nunn's letter and would have no immediate reply.

"But we're doing our darnedest to cooperate with Congress on the INF treaty," said Howard, who added that a team of congressional observers had been kept informed of the complex negotiations.

Howard said it would be impossible for the administration to comply fully with Nunn's request for a record of the negotiations before they conclude. He said, "The complete record isn't written yet."

Senior White House officials interpreted the Nunn letter as directed less at the INF treaty than at SDI.

"It's warning to us not to proceed with development or deployment of a missile-defense system," said the official, who observed that the president remains "fully committed" to SDI.

But the White House strategy, at least for now, is to avoid a new battle on this issue with a Democratic-controlled Congress that has become increasingly skeptical of the antimissile system.

Accordingly, officials said, the Nunn letter will be studied while the administration attempts to devise a response that would avoid a new confrontation over interpretation of the ABM Treaty.

White House officials said earlier this week that they remain optimistic that U.S.-Soviet agreement is near on the INF treaty and that it is likely to be signed at a prospective November summit between the president and Soviet leader Mikhail Gorbachev in Washington.

But the potential treaty has come under fire from conservatives because Reagan has conceded that on-site inspections may not be necessary to enforce it. While trying to soothe conservative critics on this score, the White House is anxious to avoid getting into new conflicts with prominent Democratic senators like Nunn, an official said. Nunn's position as chairman of the Armed Services Committee gives weight to his threat.