Vice President Bush said today that allied leaders in western Europe have told him they are interested in interim agreements with the Soviet Union that could lead to President Reagan's goal of a ban on medium-range nuclear missiles in Europe.

Bush, ending a 12-day trip through western Europe, stressed, however, that western alliance support remains solid for trying to achieve Reagan's "zero-zero" plan. Under it the Soviets would remove all missiles aimed at western Europe in return for cancellation of U.S. deployment of new Pershing II and cruise missiles in NATO countries.

In an interview here before he returned to Washington today, Bush said, "I am not saying what the U.S. position might or might not be" on any possible interim step. "That won't be determined until we assess all this information" in Washington, he said.

His comments are the first official confirmation that the White House will be informed of western European desire for an interim agreement with the Soviets, which presumably would leave both sides with an equal, reduced number of missiles until a ban could be negotiated.

U.S. and western European officials said the allied leaders did not press Bush and in most cases were vague about what they wanted. They appeared willing to leave the details and the timing up to the Americans.

Bush said he was "quite sure" that Reagan would be interested in Bush's recommendation and assessments after such fresh exposure to an issue that is at the center of East-West tensions and a key political issue in western Europe.

Throughout the trip, all of the allied leaders joined Bush in offering strong public endorsements of the zero-zero plan. That calls for Moscow to get rid of about 600 missiles deployed in the Soviet Union and aimed mostly at western Europe in return for the West not deploying 572 new U.S. missiles scheduled to begin arriving in Europe in December if no arms agreement is reached.

The allies agree that elimination of all such weapons is the best solution. But the Soviets have rejected this plan.

In recent weeks, European leaders have made several statements suggesting that, if the zero plan is not attainable by year's end, interim steps might be taken to balance reductions of Soviet missiles and those the West plans to deploy.

British Prime Minister Margaret Thatcher, West German Chancellor Helmut Kohl and Foreign Minister Hans-Dietrich Genscher, Italian Foreign Minister Emilio Colombo and Dutch Prime Minister Ruud Lubbers are among those who have hinted at such actions.

"I've read those published statements, and I think they are backed up in private," Bush said to two reporters who covered his trip.

Under questioning, Bush said the allies "have an interest" in trying to find a more refined or subtle formula that would preserve zero as a goal but that might ease East-West tensions while achieving a military balance.

Privately, some officials also have said that, even if the Soviets reject any new U.S. initiative, the fact that it was offered would help western European leaders politically when the time comes to begin Pershing and cruise weapon deployment.

The decision on offering new initiatives will be up to Reagan, said Bush, who gave no indication what would happen.

He said the allies present "an absolute solid front" in feeling that the West "must not appear to be unwilling to negotiate" and that the zero plan should not be viewed as a "take-it-or-leave-it proposal."

At every stop, Bush has challenged the Soviets to present arms reductions plans that go well beyond the one offered recently by Soviet leader Yuri V. Andropov.

His would reduce the Soviet missile count in the western Soviet Union to 162, the same as in the independent French and British forces. But it would still allow no U.S. weapons. The West rejects this because it preserves the Soviet missile monopoly over the United States and because only U.S. weapons are committed to the defense of Europe's non-nuclear countries.

Bush said that, while "there's hope the other side will be more forthcoming," there is "enormous skepticism" on that point among the allies. "There is no feeling that I have been able to detect that Andropov is soft . . . nor does anyone really feel he's reasonable," Bush said.

If Moscow does not offer new proposals, the Reagan administration must decide if it will make a move to break the deadlock.

Authoritative sources say Genscher has been pressing hardest for a new U.S. initiative for an interim solution that would come about fairly soon. Genscher is chairman of the junior political party in Bonn's coalition government, and his party may not gain enough votes in the West German election March 6 to remain in Parliament.

Conservative German Chancellor Kohl, however, appears convinced that he is heading for election victory. Well-placed U.S. and West German sources say Kohl made no demands of Bush about whether or when a new U.S. initiative should be undertaken. Nor did he offer any numbers of weapons on both sides that might be considered as a balanced new proposal, they said.

Sources say the Dutch and Belgians, who have been vague about whether they will accept their planned share of cruise missiles, appear most worried politically by the situation and less certain about the future course.

Bush said he provided the Europeans "every opportunity . . . to leave aside any considerations" about "whether somebody is going to feel you are not being true to a commitment if you think we ought to vary things a little bit."

But he said he emerged from those meetings "feeling very reassured" about the strength of the alliance. He said he was pleased with the solidarity on the willingness to deploy the new missiles in December but "that isn't to say there isn't any unease about it."

Sources say that Bush asked for European advice but that, if it was not offered in detail, he did not press for it. It seems to be the paradox, as one official put it, that the Europeans want to be consulted but apparently did not consult in much detail.

Bush's mission here was to help persuade the western European population that Reagan is interested in arms control. Bush said Reagan's original zero-zero proposal in November, 1981, initially captured the high moral ground and public opinion with its proposed total ban.

"But I think we . . . the alliance failed to keep that message out in front," Bush said. "And for Andropov to emerge, what with that sorry record as a man of peace a reference to Soviet activities in Afghanistan and Poland and occupy the high ground because a lot of us left the field is just wrong."

So Bush has been hammering home in speeches and news conferences, which he acknowledged are reminiscent of an election campaign, that the zero-zero plan is a sound, moral position.

Judging from press coverage, editorial commentaries and discussions with diplomats in allied capitals, he has been doing well.

Reagan's actions seemed to hurt the trip most. There was skepticism about his "open letter to the people of Europe" in which he proposed meeting with Andropov to sign a zero-zero agreement already rejected by Andropov. But reports the next day that Reagan acknowledged he was responding to Andropov's propaganda did more harm to U.S. credibility.

Bush said that while he cannot be sure he thinks "This has been a useful trip. Inside, I can tell you I feel pretty good about it. I think it's given us the opportunity to make a handful of key points. It's gotten attention. There have been a few negative things, but basically it's been worthwhile and . . . there's something important about repeating fundamentals."

Asked whether he would offer his assessment to Reagan, Bush said, "That is one of the few things that vice presidents are useful for. I mean I don't have a lot of line responsibility and this, in my view, is a very important trip and I do think the president will be interested in my own judgment."