The Carter administration fought yesterday to keep its two peace initiatives in southern Africa from collapsing in the face of rising black African anger and suspicion of Washington's recent dealings with the white rulers of Rhodesia and South Africa.

In a day of intense diplomatic consultations at the United Nations and in the capitals of black African states bordering Rhodesia, the administration sought to persuade key African leaders to give the initiatives on Rhodesia and Namibia a little more time instead of opting for a total commitment to guerrilla warfare and international economic confrontation.

U.N. Secretary General Kurt Waldheim presented a report on Namibia to the Security Council that in effect asked African nations to accept the temporary compromise reached last week by a U.S.-led delegations and South Africa. U.N. and U.S. officials indicated Waldheim was preparing to send a special representative to continue talks with Pretoria if African nations do not seek to block this move.

The effort to buy more time on Rhodesia centered on Zambia's President Kenneth Kaunda, who looked out at the administration from Lusaka for meeting with Rhodesian Prime Minister Ian Smith in Washington last Friday, the day after Rhodesian aircraft and troops launched a series of punishing raids deep into Zambia that killed hundreds.

With the reported death toll continuing to rise, the State Department issued strong new criticism of the raids yesterday at about the time Kaunda was describing earlier U.S. statements as "lukewarm condemnation" that offered support to Smith and the three African nationalist leaders who role with Smith on Rhodesia's Executive Council.

"We especially regret that these attacks were carried out while the Executive Council was traveling in the United States emphasizing its readiness to negotiate," the State Department declared in a press statement issued at the daily briefing.

"This dramatic and untimely escalation will not bring about an end to conflict; it inflames the attitudes of other parties and could confound efforts to promote meaningful negotiations." the statement continued.

Smith spent two weeks lobbying in the United States after the State Department reversed previous policy and, ignoring African protests, granted him a visa. He met with Acting Secretary of State David Newsom on Friday and then announced that he would be willing to attend an "all-parties conference" to negotiate with the guerrilla forces that are putting increasing pressure on the Rhodesian army in the six-year-old war for control of the rebel British colony.

Smith said that he had asked only that no precondition be set for such a conference and that he had received such assurances, a statement that Kaunda picked up yesterday in saying that he refused any conference "based on the new Smith-Angle-American proposals in Washington."

American diplomats sought to meet with Kaunda yesterday in Lusaka to explain the Carter administration's understanding of what Smith has agreed to, and to assure the Zambian president that U.S. policy on a Rhodesian settlement has not changed, a senior U.S. official said.

But Kaunda was not available for a meeting, and the assurances were conveyed to the Zambian government at a lower level, according to the official. Meetings have been requested with the leaders of the other "front-line" African states that support the guerrillas to explain that a recent U.S. British package of proposals did not represent any departure in U.S. policy, as the front-line states fear, the official added.

In Salisbury, Smith, who returned home Saturday, said that airborne commando raids "against foreign-based terrorist camps would continue and, if need be, will be increased," United Press International reported.

African concern over the impact of Smith's visit in Washington was mingled at the United Nations with confusion and misgivings over the results of negotiations in Pretoria last week over Namibia between the five-nation "contact group" and South Africa.

he ministerial-level western group, which included Secretary of State Cyrus R. Vance, won only limited agreement from Prime Minister P. W. Botha to continue talks about U.N. supervised election for the dispute territory, also known as Southwest Africa.

Botha announced that South Africa would go ahead with uniliateral elections in Namibia in December, despite western efforts to get him to call off those elections and endorse fully the U.N. plan.

In a report required to be submitted yesterday by earlier Security Council resolutions, Waldheim said that after being briefed on the Pretoria negotiations, "I have initiated further consultations with others concerned."

Informed sources said later that Waldheim was now consulting with the front-line states and with the Southwest Africa Peoples Organization (SWAPO), the guerilla group that is leading a low-level but escalating insurgency in the desert territory.

The ambassadors of the five-nation group were meeting together yesterday, as were the representatives of African nations, to discuss the next steps in reacting to the limited crompromise.

A similar meeting of African nations Friday produced an outpouring of confused and angry questions about the West's intentions, according to U. N. sources, and led to a statement from the Organization of African Unity expressing dismay over what was seen as a weakening of western resolve to force South Africa to get out of Namibia.

But this dismay and anger is being stated largely in private, U.S. and U.N. officials said, raising hopes held by the officials that the African nations will not seek an immediate Security Council meeting that would trigger calls for economic sanctions against South Africa.

Waldheim is reportedly preparing to send his special representative, Marti Ahtisaari, to Windhoek, the provincial capital of Namibia, for a new round of talks by the end of the week unless African resistance makes it impractical.

The Carter administration has been sharply critical of apartheld and has placed emphasis on winning cooperation from the front-line states and Nigeria to resolve the wars in Rhodesia and Namibia. The Washington talks with Smith and Carter's personal invitation to P. W. Botha to visit Washington in return for South African help in resolving the Namibia conflict now appear to be creating growing doubts in African capitals about a possible shift in African policy, U.S. sources acknowledge.