President Reagan yesterday declared the SALT II strategic arms treaty dead, but said the United States would push for a "better deal" with the Soviet Union to reduce superpower arsenals.

In a day marked by repeated White House efforts to clear up confusion caused by the president's remarks at his news conference Wednesday night, Reagan endorsed a statement by his chief spokesman, Larry Speakes, that the SALT II limits "no longer exist."

"If we take future actions in the area of arms control, it would be for reasons other than the SALT agreement," Speakes said. "Our strong preference is to enter into a regime of mutual restraint and reductions with the Soviet Union."

Several hours after Speakes declared the SALT II limits to be nonexistent, another White House spokesman, Edward P. Djerejian, issued a statement saying, "Restraint from our point of view is not dead. We hope mutual restraint is not dead, but that depends on Soviet actions."

Confusion over the president's intentions was evident on Capitol Hill yesterday, where the House Foreign Affairs Committee spent most of the day debating arms control issues before approving a nonbinding resolution urging him to comply with SALT II as long as the Soviets do. For the past seven years, both superpowers have said they are abiding by the treaty, which was signed in 1979 but never ratified by the Senate. The administration contends the Soviets have violated the treaty.

Also yesterday, Assistant Defense Secretary Richard N. Perle said the Soviet Union would gain no military advantage from the scuttling of the SALT II limits. In a luncheon with Washington Post reporters and editors, Perle said "there is no military rationale for deployment by the Soviets of more weapons than they are permitted to have under the SALT II treaty."

He conceded that the Soviets might not dismantle older SS11 and SS13 missiles once released from the treaty obligations, but described the significance of this as "trivial."

Reagan, in his nationally televised news conference Wednesday, suggested that his May 27 announcement on the SALT II treaty was not final. Yesterday, White House officials emphasized that Reagan did not intend to suggest that he would back away from the announcement.

Reagan has said the United States will not actually exceed the SALT II limits until the 131st B52 bomber is armed with air-launched cruise missiles later this year, and that he would take Soviet actions on arms control into account before going over the limits.

Speakes said the United States "indicated that we will no longer be bound by the numerical limits" of the treaty. "We have not violated it yet. We may not go over it in the fall."

"The decisions we make on arms reductions on our side will be based on Soviet behavior in three categories," Speakes said.

The first, he said, is the "prospects for true arms reduction" at the Geneva talks. The second is "the superiority question. We won't let them have superiority over us, and we will continue to modernize." The third "is their continuing pattern of violations, whether there is any abating of violations of the SALT treaty."

Speakes suggested that the administration would continue to use the SALT limits as criteria for Soviet behavior even though the United States has declared that the limits no longer exist.

At a picture-taking session yesterday, Reagan endorsed Speakes' statement that the treaty limits "no longer exist" and said, "We are going to try and replace it with a better deal."

Paul H. Nitze, a top administration arms control adviser, told reporters yesterday there have been no discussions with the Soviets about new interim restraints on strategic weapons but there would be if the superpowers began "serious negotiations." Nitze said the Soviets "appear recently to have given some greater indications of potential movement in their position," but said it appeared to predate Reagan's May 27 announcement.

Speakes said "we do find it very interesting" that the Soviets have recently made several new arms control proposals "in view of" Reagan's May 27 announcement. Speakes and Perle both refused to comment on a new Soviet proposal on strategic arms presented in Geneva on Wednesday.

But other officials said that the issues of how and when to respond to the new offer, which was first broached informally in Geneva May 29, are widely seen within the government as the next intra-administration battle over arms control.

Under the Soviet proposal, according to U.S. sources, the United States would agree to continue its adherence to the 1972 Antiballistic Missile treaty for 15 to 20 more years, in return for Soviet concessions on sharp reductions in offensive arms. Under the Soviet proposal, this would be done in a protocol to the ABM treaty that might not require passage by two-thirds of the Senate.

One source said there are unofficial indications the Soviets might agree to a guaranteed time period for the ABM treaty well short of the numbers originally proposed.

In the interview at The Post yesterday, Perle said critics in Congress have greeted Reagan's announcement on SALT II with "near hysteria" out of fear that it would launch a new arms race. "In fact," he said, "we don't project any significant differences in the Soviet force in the absence of the SALT agreement, nor is our force going to be different."

"The difference between SALT II and no SALT II is likely to be in the retirement by the Soviets of some SS11s and SS13s," he said. "It seems to me trivial if they keep those SS11s and SS13s." He added, "If they think it's in their interest to build more weapons, then they will even if SALT II is still in effect."

Perle also said the Soviets have been backing away from statements made at the Geneva summit. He recalled the pledge by Reagan and Soviet leader Mikhail Gorbachev to seek progress on arms control in areas where there is common ground, and said the Soviets have since been "introducing proposals at a furious pace that have detracted from that rather narrow . . . set of objectives."

He also described Reagan's decision to abandon the SALT II limits as important because it demonstrated to Moscow that Reagan was not a weak president and would follow through on his previous vows to do so if the Soviets continued to violate the treaty.

In the House committee vote, four Republicans joined the Democratic majority in adopting the resolution by a 29-to-11 vote. The measure is expected to be on the House floor next week, and is seen by House Democratic leaders as a prelude to a possible later attempt to enact binding legislation that would prohibit spending to deploy weapons that would exceed the SALT II limits. A bipartisan group of senators is considering a similar two-track strategy.

To meet Republican objections, the original House resolution was revised by the committee to acknowledge administration claims of Soviet violations of the treaty.

"What's confusing now is where we are," committee Chairman Dante B. Fascell (D-Fla.) said of the various statements coming from the White House.

Replying to a charge by John H. Hawes, deputy assistant secretary of state for political-military affairs, that the resolution would undercut the administration's flexibility in arms control negotiations, Fascell said, "I gather the president is preserving his options, and this [resolution] doesn't affect his flexibility."