The European allies are unlikely to join the United States in cutting off trade and diplomatic relations with Iran because they fear it could completely alienate the Iranians from the West and drive them into the arms of the Soviet Union, officials in a number of European capitals indicated today.

Instead, the allies hope to agree among themselves on less drastic steps they could take "to demonstrate our solidarity with the United States without completely compromising our position" in Iran, in the words of an Italian official that echoed those of other European diplomats.

The reactions of the European diplomats contrasted with an official optimism in Washington, where a State Department spokesman said the initial response of U.S. allies to President Carter's new steps has been "supportive."

Secretary of State Cyrus Vance called in ambassadors from about two dozen friendly countries to seek support for the U.S. moves, officials in Washington said.

"We have been talking with friendly countries and have been consulting with others. We would like to say that all of the replies have been supportive," State Department spokesman David Passage said. He did not list the countries.

Government sources in Britain, West Germany, Italy, the Netherlands and Denmark all said today that they would not take any action until a coordinated position could be worked out by the nine European Common Market countries.

Japan also appeared reluctant to take the tough diplomatic and economic steps sought by the United States, and sources in Tokyo said Japan would try to move in concert with the European allies.

Masayoshi Ito, Japan's chief Cabinet secretary, told reporters that the U.S. requests are "quite serious and grave." Whatever the Japanese response is, sources there said, it will be represented as Japan's own initiative and not as a caving-in to American pressures.

The Common Market, Japan and about a dozen other countries -- including Austria, Norway, Sweden, Australia and New Zealand -- have been asked by the United States to join in economic sanctions against Iran and to recall their ambassadors from Tehran to put pressure on Iran to secure the release of the 50 Americans held hostage there.

Deliberations among the foreign ministers of many of these nations began tonight in Lisbon, where they were gathering for a meeting Thursday of the 21-nation Council of Europe to discuss East-West relations.

European officials expect consultations on the Iranian crisis to continue for several weeks, possibly including a meeting of the Common Market foreign ministers sets for April 21 and a tentatively scheduled summit of Common Market leaders at the end of the month.

Government sources in Italy, which currently holds the Common Market presidency and is coordinating the consultations, emphasized the European governments realize Carter was forced to act by the failure of recent negotiations with Iran and that there "must be some demonstration of solidarity" with the Americans.

Pointing out that such a demonstration could fall well short of severing diplomatic and trade ties, they suggested issuing a new strongly worded European statement, gradually reducing senior staff in European embassies in Tehran, and stopping the sale to Iran of spare parts for its oil industry and transportation systems. These suggestions were noted with interest by officials in other European capitals.

Sources in several countries said there were no plans to recall their ambassadors from Tehran, although this is to be discussed by Common Market foreign ministers. In Bonn, government spokesman Armand Gruenewald said the possibility of recalling the West German ambassador to Iran "is not at present under discussion."

A Defense Ministry spokesman in Bonn said 155 Iranian military officers were still undergoing training in West Germany and that no decision had been made on whether to expel them. The United States this week expelled all Iranians undergoing military training there.

Sources here and elsewhere n Europe said it would be better for both the United States and the rest of the West if European countries maintained some contact with the Iranians, particularly the relatively moderate figures such as President Abol Hassan Bani-Sadr, whose position has been weakened by recent events.

"We are hesitant about a total break of relations with Iran," said a Danish government source. "It would leave the field open for others."

"Breaking off diplomatic relations would be a mistake," said an Italian official. "Our concern is that an escalation of the crisis will force Iran to align with the Soviets and burn all its bridges with the West."

A recent speech by Iranian Foreign Minister Sadegh Ghotbzadeh was cited here as an apparent attempt to improve Iranian relations with Europe as an alternative to the United States or the Soviet Union. "Our policy is to minimize our relations with the superpowers and get rid of their dominiation," Ghotbzadeh said, "and to have wide relations with Europe."

The European allies are even more reluctant to join the United States in stopping trade and financial transactions with Iran. This could cause serious problems for some European countries.

Britain last month imported only 4 percent of its oil from Iran, but its monthly trade with Iran still exceeds $40 million and its important role as an international banking center depends on doing business with major oil-producing nations.

West Germany's trade with Iran fell from about $3.6 billion in 1978 to about $1.2 billion last year, but it is still Iran's largest trading partner and imports 10 percent of its oil from Iran.

German officials are concerned about the long-term supply of such a substantial quantity of oil, reported Washington Post correspondent Bradley Graham in Bonn.

Italy's dependence on Iranian oil has fallen from 13 percent of its total imports a year ago to just 2 percent now, according to special correspondent Sari Gilbert in Rome. But 1,600 Italians still live in Iran, working on more than $3 billion of construction and other projects.

West German and British officials took pains to point out they have been supportive of the United States during the Iranian crisis and will continue to be.

Although the West German response to the United States request for sanctions support is being considered quite cautiously, Bonn spokesman Greuenewald said, there should be no doubt that West Germany will act "as a friend and partner of the United States."

Britain's ambassador to the United States, Nicholas Henderson, in a television interview today, pointed out that Britain and other allies already have limited credit and cut off arms sales to Iran. Britain, he added, "spearheaded" efforts to enact a U.N. economic sanctions order that was vetoed in the Security Council by the Soviet Union in January.