President Carter met with his top foreign policy advisers yesterday as his administration began formulating a U.S. response to the presence of 2,000 to 3,000 Soviet combat troops in Cuba.

Secretary of State Cyrus R. Vance is expected to announce the administration position at a news conference scheduled for 11 a.m. today.

White House officials, saying that Vance had been designated to speak for the administration on the issue, declined to comment on the meetings of the foreign policy advisers at the White House yesterday.

However, one White House official suggested that the United States will attempt to contrast Cuban President Fidel Castro's welcome for Soviet troops on Cuban soil with Cuba's portrayal of itself as a leader of the world's "nonaligned" nations.

"The presence of Russian troops in Cuba poses a much more serious threat to Mr. Castro's supposed status of nonalignment than it does to the security of the United States, " the official said.

Cuba is currently hosting the sixth summit of nonaligned nations in Havana, where there have been charges by some of the nations that Castro is trying to draw them into the Soviet sphere. In a speech to the summit Monday, Castro denied the charges and denounced "Yankee imperialism" and its "dirty scheming" to undermine Cuba's position of nonalignment.

According to one presidential aide Vance was chosen to make the administration response because he is "an appropriately high-level official," underlining the seriousness of the U.S. view. The Soviet troops are not considered a military threat to the United States, but the State Department has said they are a "matter of concern" to the administration.

Officials estimate that there are about 3,000 Soviet troops in Cuba. Intelligence reports of the troops surfaced last week, prompting questions of why the Soviet buildup in Cuba was not detected earlier.

Some Soviet troops have been in Cuba since 1976. But the extent of the Soviet buildup and the fact that it involves combat units was not discovered until last week.

The Senate Foreign Relations Committee postponed a hearing scheduled for yesterday until today on the failure of U.S. intelligence agencies to detect the troops earlier. The committee has called for testimony from Central Intelligence Agency Director Stansfield Turner and Undersecretary of State David D. Newsom, and will also be briefed today by Vance.

Chairman Frank Church (D-Idaho) said in announcing postponement of yesterday's hearing that the committee wants to find out what "possible jusitification" there is for Soviet combat troops in Cuba.

"The United States cannot permit the Soviet to establish a military on Cuban soil," Church said, "nor can we allow Cuba to be used as a springboard for real or threatened Russian military intervention in the Western Hemisphere."

Castro also should explain to the world "how his willingness to permit Soviet troops to hold military maneuvers on the island conforms to his professed adherence to the principles of nonalignment," Church said.

Yesterday's hearing was postponed in part because Turner was at the White House for the series of meetings on the U.S. reponse. Others involved in drafting options that went to Carter yesterday included Vance, Defense Secretary Harold Brown and national security adviser Zbigniew Brzezinski.

The president also met with the foreign policy advisers during the day, officials said.

In his only public appearnace yesterday, Carter devoted his attention to a domestic issue-- pending hospital cost containment legislation. Addressing approximately 200 supporters of the legislation at a White House briefing Carter predicted an all out effort to defeat the measure by a "powerful, well-organized lobby" representing hospitals.

Earlier, White House press secretary Jody Powell said the hosptial cost containment vote will provide "a true test" of Congress' willingness to combat inflation.