The defeat of Israel's Labor Party yesterday has jolted American officials here on the eve of new talks with the Soviets on the Middle East.

Although State Department officials said today that it is still too early to assess the full meaning of the election, it is privately acknowledged that the result appears to have thrown a monkey wrench into a major Carter administration foreign-policy campaign to press for a settlement to the lingering Arab-Israeli conflict.

That campaign was based on the presumption that the Labor Party would either stay in power or remain as the leading force within some new coalition.

The White House is now confronted not only with a new government that could take a long time to get organized, but also with a likely right-wing coalition that could dig in its heels even deeper in opposition to the kind of territorial concessions that the White House envisages as reasonable. On the other hand, senior officials here noted with some interest that the tone of Likud Party leader Menachem Begin's initial remarks on a peace settlement was moderate and that the coalition he eventually forms may also be more moderate than expected.

In a brief session with reporters here, State Department officials also said it was too early to draw any conclusions when asked if they thought that the Carter administration had contributed to the election results by pressure on the previous Labor government.

The White House effort to press for a Middle East settlement is one of two major foreign-policy initiatives of the new administration. The other is the quest to find some new agreement with the Soviets on further limitations of nuclear weapons.

U.S. Secretary of State Cyrus Vance arrived here this morning to begin two or three days of discussions with Soviet Foreign Minister Andrei Gromyko on both subjects.

Since there was little detectable optimism among U.S. officials here on the prospect of immediate progress on the arms question, the Geneva talks got under way today in a somewhat gloomy atmosphere, from the U.S. point of view.

In a signal of Washington's willingness to allow at least the appearance of a greater role for Moscow in the Middle East peace search, State Department officials volunteered today that they will discuss with the Soviets the possibility of a system of regular meetings to discuss the issue. The region is one in which the Soviets have lost both influence and face in recent years, and they have been pressing for a greater role in the peace search.

Under questioning, however, officials rejected this interpretation, claiming that the U.S. suggestion is mostly an effort to achieve some regularity in meetings that have been held only sporadically in the past.

Officials pointed out that the two countries are cochairmen of the long-dormant Arab-Israeli Geneva conference on the Middle East, which has been stalemated since its opening session late in 1973. If that conference were to reconvene later this year, then technical collaboration is needed between officials of both countries with various Middle East contacts, officials said.

It was also pointed out that the question of gaining Palestinian recognition of Israel's right to exist remains the biggest single obstacle to serious negotiations, in the U.S. view, and that the Soviets have contacts with the Palestine Liberation Organization. That is one area officials said, where the Soviets could play a constructive role, although it is not clear whether they will.

The Soviets are also pressing for reconvening the Geneva conference because it gives them at least some formal role in the world spotlight on a Middle East settlement.

U.S. officials said that the more regular meetings would in no way restrict Washington's ability to act on its own.

The proposal for regular meetings and to share the spotlight may also be an effort to create some good will with the Kremlin that could improve strained relations in other areas. It might also be interpreted in Israel as suggesting additional U.S. pressure to be more flexible on settlement terms.