U.N. Ambassador Jeane J. Kirkpatrick declared today that the Reagan administration's foreign policy team is united in unswerving opposition to negotiations as a way to end the Salvadoran civil war.

"It constitutes the official position of Washington and the State Department, the White House and the U.S. government," she said at the close of a two-day stay in the Salvadoran capital.

Kirkpatrick's categorical language, in a departure news conference, came in response to a report from Washington that State Department officials were suggesting consideration of a two-level policy of continued support for the Salvadoran government's war effort with simultaneous attempts to open channels to the leftist guerrilla movement.

The administration so far has backed the Salvadoran government's refusal to negotiate, despite grumbling in Congress. Kirkpatrick's comments appeared calculated to assure the Salvadoran leadership that it need not fear crumbling in the U.S. position.

At the same time, Kirkpatrick has been an advocate of a firm U.S. stand here, opposing any suggestions of dealing with the guerrilla movement at a negotiating table. Against that background, her comment seemed to be an expression of confidence that her view prevails in the administration.

The State Department declared yesterday in Washington that the U.S. position "is clear and will not change."

"We strongly oppose negotiations over power-sharing, believing that only through elections can legitimate governments emerge," a spokesman said.

Kirkpatrick reiterated that position today, reading carefully from a cabled copy of the State Department statement that U.S. Ambassador Deane R. Hinton also has communicated to the Salvadoran government.

In the past, however, the United States has made a distinction between "negotiations over power-sharing" and "dialogue" with the guerrilla movement through intermediaries. The position reiterated by the State Department and Kirkpatrick appeared to leave this distinction intact, with an opening for the two-level policy reportedly being discussed.

The idea of any contact with the guerrillas--whether negotiations or dialogue--is anathema to the Salvadoran right wing and many in the U.S.-supported armed forces. Partly as a result, the government of provisional President Alvaro Magana has declared its opposition to any such indirect dialogue, insisting elections are the only avenue for the left to participate in Salvadoran politics.

Kirkpatrick, on a tour of four Central American nations and Venezuela, stopped here at a particularly welcome time for the Salvadoran leadership.

She was able personally and immediately to address any doubts brought on by the Washington report of a possible shift in U.S. policy. In addition, her presence here gave Salvadoran officials a counterweight to this week's complaints in Congress suggesting U.S. military aid should be made contingent on El Salvador's willingness to negotiate with the guerrilla movement.

But Kirkpatrick steered away from questions on her assessment of the war in the light of recent guerrilla successes. She argued that she knew little about guerrilla warfare and suggested the same applies to correspondents covering the conflict here.

On her way to El Salvador Wednesday, however, news agencies reported Kirkpatrick told journalists in Honduras that "the Salvadoran guerrillas aren't winning anything, nor do they hope to win."