President Reagan did not intend to suggest at his news conference any willingness to scale back his proposed $1.6 trillion, five-year defense buildup, White House spokesman Larry Speakes said yesterday.

"I'm saying the man will not back off from his commitment to restore this country's military capabilities," Speakes said. "I don't look for him to back down one iota on what he intends to do on defense."

That commitment means Reagan will insist on "at least" 7 percent annual growth in defense outlays after inflation, Speakes said.

The president told Speakes of his determination to stick by the 7 percent real-growth rate just after the news conference Thursday night, as he stood by a White House elevator. Speakes quoted Reagan as saying, "I'm sticking to what I said, 7 percent."

Speakes said later that this was only a "minimum figure" that Reagan would ask for, and that he has not decided how much more to seek from Congress for the Pentagon in fiscal 1984.

But the administration's projections in the budget submitted to Congress last February suggest it had envisioned defense outlays growing by more than 7 percent after inflation. In that document, the administration projected 8 percent real growth in fiscal 1984 and 9.6 percent in fiscal 1985.

In addition, inflation is now lower than the administration anticipated a year ago, so the same real-growth percentage may translate into fewer actual dollars in the 1984 spending plan. The administration may be able to meet its growth targets and still shave a little off last year's projections for defense.

Reagan said at his news conference that he has not made any decisions about the fiscal 1984 budget he will send to Congress Jan. 17. Only this week, Reagan got his first round of overall budget briefings.

The midterm election returns were interpreted by some congressional Republicans as well as Democrats as a signal that voters want Reagan to scale back the Pentagon buildup and tackle the nation's rising jobless rate.

Even within the administration, there is some sentiment that Reagan must show restraint in the military buildup as a way of holding down record budget deficits in 1984 and 1985 and permitting the economy to grow again.

But Speakes said yesterday that Reagan "will not back off one inch on the development of U.S. capabilities." He said Reagan did not want to send a post-election signal of flexibility on military spending at his nationally televised news conference.

Privately, some administration officials think Reagan will eventually have to settle for a modest slowdown in his defense buildup, but the politics of the situation dictate that he not appear to give ground so early in the budget cycle.

Questioned Thursday night about the calls for restraint in the military buildup, Reagan said he would look for "savings" in the Pentagon budget for 1984. He noted that "the greatest share" of military outlays are for pay, and that weapons systems require a long lead time.

"But we're looking at everything . . . I would have to say that yes, we're looking, if there are savings that can be made without delaying or setting back what we think is the improvement we must have if we're going to close that window of vulnerability that we inherited. We can't do that. The first and primary function of the federal government is the national security."

Speakes said yesterday that Reagan was talking about "management savings," and "cutting the fat out of the defense budget," instead of scaling back his ambitious military buildup.

Asked whether Reagan would consider eliminating any weapons systems, Speakes said, "Don't anticipate it, but there's been no specifics yet on that."