Henry A. Kissinger, in his first appearance before Congress since resigning as Secretary of State, yesterday urged the adoption of energy conservation measures to reduce U.S. dependence on oil imports, which he said "impairs our national security."

Appearing before a packed Senate hearing room, Kissinger, who looked tan and less portly than he was while Secretary of State, acknowledged in a low voice that the Nixon and Ford administrations failed to implement energy conservation plans.

Citing U.S. performance in the oil-consuming nations' organization - the International Energy Agency - which he helped create, Kissinger said. "Our role has not been adequate to date."

An IEA study released earlier this year ranked the United States 17th out of 18 in overall energy conservation among the leading industrial nations. U.S. imports of foreign oil during the years Kissinger served as Secretary of State surged to record levels by the end of last year, amounting to 42 per cent of total oil consumption.

Kissinger, testifying as chairman of the Board of Advisors to the Alliance to Save Energy, a volunteer organization established by Sen. Charles Percy (R-Ill), was warmly received by members of the Senate Energy Subcommittee on Conservation and Regulation chaired by J. Bennett Johnston (D-La).

In an appearance marked with little of the panoply of the past and without the battery of aides who accompanied him while he was a Cabinet member, Kissinger warned in measured tones that the United States would remain dependent on foreign oil imports over the next five years.

He expressed support for efforts by President Carter and energy advisor James R. Schlesinger to forge a national energy policy. "No administration would allow the oil producers to dictate our foreign policy," he declared.

Later, asked about policies he initiated, Kissinger quipped. "As time passes from when I served in office, my perception of my infallibility decreases."

In response to a question from Sen. Henry F. Jackson (D-Wash.), Kissinger declined to offer "any new dramatic proposals with regard to our policy toward Saudi Arabia."

Saudi Arabia is now exporting almost 10 million barrels of oil a day and has the largest proved oil reserves of any non-Communist country.

He said Carter's policy toward Saudi Arabia is "correct." That policy, which follows one that Kissinger authored, consists of maintaining a close relationship with Saudi Arabia and encouraging it to moderate oil price increases to maintain a stable world economy.

Questioned by Sen. Lowell P. Weicher Jr. (R-Conn.) on whether he advocated mandatory measures, Kissinger called for increased voluntary efforts, "mobilizing private initiative," before mandatory measures are imposed. Kissinger said he also favors eventual decontrol of energy prices.

As the cordial questioning ended, Sen. Johnston inadvertently thanked "Dr. Schlesinger" for his appearance - confusing Kissinger with his former rival, who now serves as Carter's top energy policy maker.

Kissinger told Johnston, "I'm sure he'll be glad to tell you the difference."

He then picked up his raincoat and, clutching a manila folder, nodded to the committee, walked quickly through the hearing room door, and left a trail of reporters, cameramen, and tourists behind.