SANTA BARBARA, CALIF., SEPT. 1 -- White House officials said today that they expect President Reagan will agree to be interviewed by independent counsel Lawrence E. Walsh about the Iran-contra affair.

But the officials emphasized that the issue has not been discussed directly with the president because Walsh has given no indication whether he will ask for an interview. The Washington Post, citing informed sources, reported today that Walsh probably will seek an interview this fall.

In response to questions at a briefing here today, White House spokesman Marlin Fitzwater said that "we have not heard from the independent counsel concerning any requests for direct information from the president" and that an evaluation would follow if a request is made.

"The president has said from the beginning that he would cooperate appropriately with the independent counsel," Fitzwater said. "He has provided access to his private notes, thousands and thousands of documents have been turned over to the independent counsel, and every effort has been made to cooperate."

Fitzwater acknowledged that there were precedents for testifying, but said he did not want to suggest what Reagan's "course of action" would be because "we just have no indication whether the independent counsel intends to ask the president for information or in what form."

Privately, White House officials said they expected a request for Reagan's testimony even though they had received no such word from Walsh. Fitzwater said that a representative of Walsh's office had been "fairly negative" when a White House official sought to ascertain whether Reagan would be asked to testify.

This White House attempt to discern Walsh's intentions came after a recent Wall Street Journal story on the investigation, officials said. They said White House counsel Arthur B. Culvahouse Jr. was rebuffed in his attempt to find out if Walsh wanted to question Reagan.

A White House official said that in view of this response, no one wanted to issue "an invitation" to Walsh to question the president. "The ball is in his court, and we hope it stays there," the official said.

Walsh is weighing whether to seek a statement from the president or to question him orally, the Associated Press reported today, attributing the information to "a source familiar with the case."

Administration officials, who discussed the issue on condition they not be identified, readily acknowledged mixed feelings about the prospects of presidential testimony in an investigation that could lead to broad conspiracy indictments against fired national security aide Oliver L. North, former national security adviser John M. Poindexter and others.

On one hand, officials are not anxious to help refocus attention on the Iran-contra scandal while Reagan is trying to make headway on an arms-control treaty, Nicaraguan peace negotiations and the confirmation of his Supreme Court nominee, Robert H. Bork.

But an official said "the strong suit" of the president in the Iran-contra affair, which has severely damaged his public approval ratings, has been his willingness to cooperate with investigating authorities, including the Tower board, joint congressional committees and the independent counsel.

The official emphasized that Reagan wants to continue to cooperate, but would not decide what he should do until a formal request is made by Walsh and evaluated by the White House counsel and staff.