The Carter administration's determination to reconvene a Geneva peace conference even on terms that might be harmful to Israel could lead to "a political fight with the United States in the near future," Israel's new deputy prime minister-designate, Yigael Yadin, warned today.

Yadin, whose Democratic Movement for Change voted last night to join Prime Minister Menahem Begin's coalition government, said in an interview that a recent trip to the United States had persuaded him to bring his moderate faction into the rightist government.

He said the trip also convinced him that the Carter administration is dangerously "preoccupied" with the problem of the Middle East.

"When you are there in the midst of a very hectic period for the United States - Panama, energy, taxes, unemployment - and when you see how preoccupied the administration is with the Middle East issue," it is all a little bit frightening, Yadin said.

"In the normal way it would be a compliment but I am afraid that it shows that we are very quickly approaching - let us call it a friendly confrontation - but definitely a confrontation with the United States," he said.

In Yadin's analysis, the only "asset" that the United States has as an arbitrator, as far as the Arabs are concerned, is that the United States can put pressure on Israel.

In talks with administration officials, including Secretary of State Cyrus Vance and national security adviser Zbigniew Brzezinski, Yadin said, "it was quite clear that at the moment the administration is set first and foremost on the reconvening of Geneva."

Yadin said he was not opposed to the Geneva talks, but he feared that the United States was "following the line of most extreme resistance - in this case the Syrian line. They are trying all the time to get terms which will be agreed upon by the Syrians . . . and the net result may be that the terms for Geneva will end up totally unacceptable to Israel."

Yadin said he found it especially disconcerting that this preoccupation with Geneva was being linked with "mounting pressure is the United States on the energy problem." He said he was surprised to hear two high U.S. officials say "quite openly that the whole thing, the price of the gallon, depends on one thing and one thing only, and that is whether or not there is a Geneva conference."

He said this was "dangerous and inflammatory" and that everybody knew it was not true. He said it was being used as an excuse to cover up the Carter administration's failure to solve the energy problem at home and that it was being used as a "stick to force Israel to go to Geneva by trying to incite public opinion in the United States."

Equally alarming, in Yadin's view, was what he saw as an effort "to tell American Jews that if they did nit agree with the President's views in their efforts to help Israel, their loyalty to the United States might be put in question." Yadin said that this was not the official Carter position but that it is "definitely inspired by some people within the administration."

Yadin said that although as effort had been made to put a wedge between Israel and its American supporters, both Jews and non-Jews, this effort had backfired. He said that he was glad to see that Israel's supporters were "all in fighting spirit."

Americans in the administration and outside it had urged him to join the Begin government, Yadin said, because they wanted to see a more moderate element as a counterbalance to some of the right-wing Likud hawks.

American Jews who opposed Likud said they would like a moderate influence within the government, Yadin said, "while Americans who support the Likud wanted us to join Bergin in order to strengthen his position."

Yadin said he did not want to over estimate the ability of his party to moderate the Likud but that he felf the Democratic Movement for change could have significantly more control over events from within the government than from outside.

Despite the "basic divergence of opinion" between his party and Begin's on the ultimate solutions for peace in the Middle East, Yadin said, there was complete agreement on three main issues: no dealing with the Palestine Liberation Organization; no Palistinian state in the occupied territories and no return to 1967 borders. He said that there should be no illusion that his party's joining the government would change the government's views on those points.

Where his party differs from the Likud is that "for the sake of peace we are ready for territorial compromises on all fronts," Yadin said, and it there were to be a Geneva conference, "and if negotiations should take place in a sensible manner," then he tought his party might be able to influence the negotiations.

Yadin said that his party is also opposed to the government's policy of establishing Jewish settlements among the occupied West Bank's Arab population.

"I told the prime minister that it is very difficult even for our friends to swallow this settlement policy and that this problem bothers everybody in the United States," he said.

With four Cabinet seats, the Democratic Movement for change will constitute 25 per cent of the government and will be represented on all important committees. It's parliamentary strength, with 15 seats, is only 12 per cent of the total. The new cabinet is to be presented to parliament early next week.