An outspoken Edmund S. Muskie arrived in Europe tonight for the first time as secretary of state, tying the future of Soviet-American relations to a Soviet withdrawal from Afghanistan, and calling on NATO allies to stand firm on broad economic sanctions against Iran.

In a 40-minute press conference 33,000 feet above the Atlantic, followed by an airport statement on arrival here, Muskie also urged European nations to refrain from initiatives that, in U.S. eyes, could undercut the Camp David Mideast peace process. Statements and proposed U.N. resolutions by European nations on the Palestinian issue are under consideration because of impatience with the U.S.-sponsored Egypt-Israeli negotiations.

Muskie is to meet senior Western European diplomats at NATO headquarters here Wednesday, and Soviet Foreign Minister Andrei A. Gromyko in Vienna Friday.

In a more assertive public style than that of his immediate predecessor, Cyrus R. Vance, Muskie used the plain language of his 22 years in the Senate, rather than the caution of a diplomat, in describing his objectives on this trip and in meeting the multiple challenges of American foreign policy.

In contrast to the usual "background" rules for official talk aboard the secretary of state's aircraft, Muskie spoke "on the record" for direct attribution.

With the backing of a new top-level Carter administration review, Muskie set forth a policy on Iran that would combine strong economic pressures from the United States and its allies with a series of new diplomatic initiatives.

Muskie conceded that a buildup of U.S. public pressure for quick and visible progress on the hostage issue in this election year could endanger the type of quiet diplomatic maneuvers he has in mind. He said it would be useful to diminish the visibility of the hostage issue without reducing U.S. efforts to win their release.

Asked about the issue's high public profile, Muskie indirectly criticized the news media for contributing to it, and added, "The president kept the visibility alive by tying it to his own campaign plans."

Muskie took a strong position on allied economic sanctions against Iran, adopted three weeks ago and reportedly the subject of second thoughts in some allied capitals. The Iranians are truly concerned" about the European economic measures, he said. These pressures, "given their [Iran's] economic problems, are bound to be effective pressures," he said.

Nevertheless, he acknowledged in themselves the pressures will not bring the release of the hostages. But they "surely ought to improve the climate" for a release, he added.

Muskie said that the United States "has a right to expect" the allies to live up to their commitments on sanctions and made it plain he will argue vigorously that they do so.

Earlier, before Muskie's departure from Washington, President Carter warned the allied that he expects them to keep their promise and impose sanctions consistent with those outlined in a U.N. Security Council resolution vetoed by the Soviet Union.

Asked about reports from Europe that the allies might be backpedalling toward a watered-down form of sanctions, Carter replied:

"That's one of the issues that Secretary Muskie will be discussing with the allies. They have announced publicly and informed us directly that they will carry out the sanction commitments against Iran, pending some major breakthrough in the release of the hostages, and we expect our allies to keep their commitment to us."

"Obviously," the president continued, "each country has to decide exactly the level of sanctions to be maintained, but the more compatible the sanctions are among the allies with the U.N. resolution that they originally did support, obviously the better off we are."

In line with moves made by the United States in the United Nations, the administration had anticipated that the Europeans would cut off all supplies to Iran except for food and medicine. But the latest signs from Europe are that the allies want to settle for a suspension of future deals with Iran, rather than cut off deliveries under existing contracts, and also are balking at the idea of freezing Iranian bank assets in Western Europe.

Beyond his pressure on the allies to live up to their commitments on sanctions, Muskie made clear that he is relying in the long run on "the rational forces in Iran" to see their self-interest in the release of the hostages, leading to economic progress and establishment of workable relations with the outside world.

In this respect "much is going to depend" on transfer of control of the hostages to the Tehran government from the militant captors, whom Muskie described as 'the big roadblock" to resolving the crisis.

Muskie said he is not now in a position to define the relations between the United States and Iran in "the post-hostage period." Nevertheless, he indicated that future ties and cooperation are the incentives in the "carrot-and-stick" approach to Iran that he advocates.

He hinted strongly that new U.S. feelers to Iran are under way. Muskie said the United States is encouraging "third parties," whom he did not name, to identify for Iran its stake in its own future following release of the hostages.

Concerning relations with Moscow, Muskie outlined the approach he plans to take with Gromyko, "a tough guy, a smart guy, a staunch defender, without blinking, of Soviet policies."

The strategic arms limitation treaty (SALT II), negotiated over seven years by the Kremlin and three U.S. administrations, as well as the whole range of bilateral economic, agricultural and cultural relations, is at stake, Muskie said.

"I am saying to them: The burden is on you to demonstrate to us that real normalization is truly your objective. Afghanistan, which you created, is the test.'"

Muskie said that in his view it would require a Soviet withdrawal from Afghanistan to get two-thirds of the Senate to vote now for approval of SALT II. Gromyko "must understant that," he said.

The Soviets charge that the U.S.-backed plan to place medium-range nuclear missiles in Western Europe (capable of hitting Soviet territory) is the basic reason for the deterioration in relations. To this, Muskie responded that Gromyko must understand that "a steady Soviet buildup in nuclear and conventional arms over 15 years has finally generated a reaction of its own, independent of Afghanistan."

As long as the Soviet Union continues to modernize its European missle force, "we surely have the option to do the same," Muskie added. And as for controlling both Soviet and Western missiles based in Europe under a SALT III, he said, "We can't get to SALT III unless we ratify SALT II, and Afghanistan stands right in the way."

Beyond hearing a "litany" of each other's viewpoints in the meeting with Gromyko, Muskie expressed hope that there will be "some indication on [Gromyko's] part of the priorities of Soviet concerns that we can build on to persuade them to change their policies."

Muskie said he does not expect "substantive achievement" in such a meeting, and that he expects to "leave up in the air" the possibility of future meetings with Gromyko.

On the Middle East, Muskie left no doubt of the strong U.S. opposition to European initiatives on the Palestinian issue. Such initiatives could "divert attention" from the Camp David process, relax the pressures on Egypt and Israel to continue negotiations and thus "undercut" the current U.S.-sponsored peace drive, he said.

While suggesting that understandable European concerns about oil supplies and stability in the Middle East have caused impatience with the Camp David process. Muskie maintained that any alternative to the current talks would involve delay, even "starting all over again," toward resolution of central issues such as Israeli settlements, security and land and water rights.

Muskie said he expects "very vigorous discussions" with European leaders on this issue in the next several days.