Secretary of State Cyrus R. Vance testified yesterday that the Carter administration still supports parts of the controversial United Nations resolution that it first approved, then repudiated three weeks ago, condemning Israeli settlements in occupied Arab territories.

The original U.S. vote was widely regarded as a shift in Mideast policy, and Carter, under pressure, finally disavowed it on grounds that the resolution contained references to Jerusalem that were unacceptable.

But, during two hours of hostile questioning by the Senate Foreign Relations Committee yesterday, Vance repeatedly turned aside calls for the administration to repudiate the resolution in all its aspects. He also refused to say how the United States will vote if the U.N. Security Council is asked to consider a restatement of the resolution in September.

The secretary did reaffirm strongly America's commitment to Israel's security, and he denied repeatedly that the vote for the resolution represented any change in long-standing Mideast policy. In particular, Vance asserted, the vote was not intended as a pro-Arab "tilt" away from support of Israel.

But his explanations appeared to make little headway before the obviously skeptical committee. He failed to dispel what several senators called "lingering suspicions" that the U.N. vote originally was intended as a policy switch engineered by alleged "Arabist" forces in the administration.

The March 1 vote cast by U.N. Ambassador Donald F. McHenry was disavowed by Carter two days later with the explanation that a misunderstanding between Vance and himself had prevented Carter from realizing the resolution referred to East Jerusalem as "occupied territory."

Vance, who subsequently accepted responsibility for the "failure in communications," went before the committee yesterday to explain the mixup. However, the administration made clear in advance it would not discuss secret aspects of the controversy, and Vance sought instead to use the hearing to plead for support of the administration's Middle East peace initiatives.

On Wednesday, the White House announced that Egyptian President Anwar Sadat and Israeli Prime Minister Menachem Begin will come here next month for separate talks with Carter about speeding up their negotiations on autonomy for the Palestinian residents of the Israeli-occupied West Bank and Gaza Strip.

While Vance almost wistfully tried to focus attention "on our efforts for a comprehensive peace," the committee members clearly were more interested in the implications of the U.N. vote.

Their tone was set by New York Sen. Jacob Javits, the committee's senior Republican and a strong supporter of Israel. He termed the incident an "unmitigated disaster for American foreign policy . . . that has alienated Arabs, Israelis, Egyptians and just about anyone else who could be alienated, including the Europeans."

Committee Chairman Frank Church (D-Idaho) said the U.N. resolution was "clearly inconsistent" with his understanding of U.S. approaches to the Arab-Israeli conflict, and asked: Does it signal a change in U.S. policy?"

Even Sen. George McGovern (D-S.D.), who has been criticized in the past for taking stands allegedly in conflict with Israeli interests, charged that the vote could damage the U.S. standing as "impartial mediator" between Israel and Egypt and said the United States, instead of voting for the resolution or even abstaining, should have vetoed it.

In response to these charges, Vance said the administration has gone on record repeatedly as opposing the Israeli policy of establishing Jewish settlements in the occupied territories. He reiterated the U.S. position that the future of Jewish settlements is a matter for negotiation and that Israeli attempts to impose them unilaterally violate international law and impede the peace process.

In the past, Vance added, the United States had abstained from U.N. votes on the settlements issue because "we hoped it would help lead to restraint by Israel. Unfortunately our hopes with respect to restraint in establishing new settlements did not take place."

As a result, he said, when the U.N. resolution came under consideration, the administration "in this case" decided to vote for it as a means of demonstrating to the Isralis its concern over the settlements.

He further noted that Carter, in his March 3 disavowal of the vote, restated "long-standing and well-known" U.S. opposition to the Israeli settlements. The president's disavowal, Vance said, applied only to the resolution's references to East Jerusalem, which has been under Israeli control since 1967.

But, when Javits and Sen. Richard Stone (D-Fla.) suggested that the administration clear up suspicions about a change in policy by repudiating the entire resolution and formally notifying the U.N. of its action, Vance balked. He said:

"The president of the United States has stated very clearly our position. He spoke from the capital of this country and said this is the policy of the United States. We can't make it any clearer. . . . When the president speaks, he is speaking to the whole world including the Security Council."

In addition, Vance asserted, the United States considers the resolution "as recommendatory rather than binding." That led Stone to note that the resolution, as passed, calls on a U.N. commission examining the settlements question to report to the Security Council before Sept. 1 and says the council will "convene at the earliest possible date thereafter to consider the report and the full implementation of the present resolution."

When Stone asked how the United States will vote then, Vance replied: "It would depend on what is put before the U.N. at that time. I'm not going to speculate. I can envisage a report or resolution with some items in it that we can live with."

Although Carter never explained why he found the resolution's references to Jerusalem unacceptable, it is generally understood that he wants to avoid provoking Prime Minister Begin by reiterating past U.S. assertions that East Jerusalem is "occupied territory."

Since the vote turnabout, administration officials have refused to answer questions about whether the United States still stands by that definition. Under questioning yesterday, though, Vance conceded that it remains U.S. policy to regard East Jerusalem as "occupied."

Asked whether the United States believes Jews should be allowed to live in the occupied territories, Vance replied, "That's a question to be negotiated. I hope they will be able to." But he added that, at this time, the U.S. government does not have an official position on the question. t

In another development, the State Department announced yesterday that Israeli Energy Minister Yitzhak Modai will come here next Wednesday to discuss the possibility of invoking an agreement under which the United States is obliged to supply oil to Israel during an emergency. However, U.S. and Israeli sources said it is by no means certain that Israel actually plans to invoke the agreement.