Amid increasing signs that the Western peace initiative in southern Africa is foundering upon the rocks of white and black intransigence, a summit of five African "frontline" states began meeting yesterday in the Angolan capital of Lunanda on the future of Namibia.

The meeting comes at a critical junction in Western diplomatic afforts to find peaceful and internationally acceptable solutions to both the Namibian and Rhodesian disputes to counter expanding Soviet-Cuban involvement in the area.

The United States and Britain are renewing their efforts to get the Namibian and Rhodesian nationalists to the negotiating table but the going seems to become ever tougher.

The South African raid May 4 on a Namabian refugee and guerrilla camp in southern Angola and the recent western military intervention in Zaire have served to harden the position of nationalist militants, particularly in Namibia but also among some of the frontline states.

Tanzanian President Julius Nyerere, the group's chairman, delivered a stinging attack Thursday on the Western-supported pan-African security force for Zaire and warned President Carter to stop listening to "hysterical voices" in his administration about Cuban involvement in Africa. He strongly hinted there would be less Tanzanian support for Western peace initiatives in southern Africa if the West continued on its anti-Cuban crusade.

Also last week, the Southwest African People's Organization (SWAPO), the militant Namibian nationalist group let it be known here that it will not accept the Western peace plan for Namibia in its present form and will demand that some of its key provisions be renegotiated.

Meanwhile, there has been no indication of any breakthrough in Salisbury, where the British Foreign Office undersecretary, John Graham, and the U.S. ambassador to Zambia, Stephen Low, have been holding talks since [WORD ILLEGIBLE] They are trying to convince the leaders of the new biracial transitional government there to attend an Anglo-American sponsored conference with the externally based guerrilla alliance, the Patriotic Front.

So far, the Salisbury government has refused to accept the idea of such a conference and demanded recognition of its own internal settlement for black majority rule by Dec. 31. The front has agreed to attend but, like SWAPO, it is demanding considerable alterations in the Anglo-American proposals for a negotiated solution to the Rhodesian dispute.

Meeting in Luanda this weekend are presidents Nyerere, Kenneth Kaunda of Zambia, Samora Machel of Mozambique and Agostinho Neto of Angola. A fifth frontline leader, Seretse Khama of Botswana, was not expected because he is on a visit to the United States. He is represented by his vice president.

Also at the meeting is Sam Nujoma, SWAPO president, together with a number of his top lieutenants.

Whether the frontline presidents are willing, or able, to press the Namibian nationalists into softening their position is uncertain. Neto is regarded as the only leader with any real leverage over SWAPO now but his position after the South African raid into Angola is now expected to be more intransigent.

In any case, the ability of the frontline states to pressure either SWAPO or the Patriotic Front has proven to be increasingly limited as these nationalist groups grow in size and strength and find support in Eastern Europe and China.

Commenting on the group's stand toward the Namibian peace plan of the five Western powers, SWAPO spokesmen here said they were ready to resume negotiations but would seek changes in some provisions.SWAPO broke off talks with the five nations after the South African attack into Angola in early May.

The five countries - the United States, France, Canada, West Germany and Britain - have said their plan as presented to the United Nations in April is not open for renegotiation. South Africa has announced acceptance at it 10 days before its raid into Angola.

SWAPO released here in last week the text of a brochure on the South African raid and a policy statement on the western plan for Namibia demanding that "some of its provisions be renegotiated."

Its spokesmen here say they want U.N. supervision over the transition process leading to Namibia's independence, and especially over elections for a black majority government, to be clarified and strengthened. Essentially, SWAPO wants the United Nations to be more powerful than South Africa.

South Africa has been administering the former German colony under an old League of Nations mandate since the end of World War I. It has agreed to independence by the end of this year but has been threatening to go ahead with its own election plan if SWAPO rejects with Western proposal.

SWAPO spokesmen say the organization also wants the western countries to make a public declaration that they recognize Walvis Bay, the main port, and the immediate surrounding area as an integral part of Namibia.

South Africa insists the bay area has a separate juridical status and has historically belonged to the republic and not Namibia an dthus must remain for the time being under South African jurisdiction.

SWAPO also wants a commanding U.N. role role in policing the territory and is insisting that all South African army units be removed from the northern part of the country before the elections.

Whether South Africa will agree to reopen negotiations on these and other points is regarded here as doubtful but still possible.

U.S. Ambassador Donald McHenry, who has been conducting the Namibia negotiations for Washington, seemed somewhat pessimistic when he passed through here 10 days ago.

"It's a difficult task because we have a crisis of confidence with SWAPO and I might say a similar crisis of confidence with the South Africans. South Africa doesn't believe SWAPO wants a settlement."