The long-delayed summit meeting of the Organization of African Unity will be held in Libya late next month as the result of an agreement not to have Western Sahara represented, Kenyan Foreign Minister Robert Ouko said today.

The Polisario Front guerrillas who claim sovereignty over Moroccan-controlled Western Sahara have "reluctantly agreed to stay away from the meeting," Ouko said, thus resolving, at least temporarily, the continent's worst intra-African diplomatic crisis.

Ouko said in an interview with Katharine Graham, chairman of the Washington Post Co., that Tanzanian President Julius Nyerere had persuaded the Western Sahara delegation to absent itself from the summit in a meeting with Polisario Chairman Mohammed Abdelaziz in Dar es Salaam.

Tanzanian Foreign Minister Salim Ahmed Salim brought a message from Nyerere to Kenyan President Daniel arap Moi yesterday, disclosing the agreement resolving the eight-month-old problem, Ouko said. A summit was not possible with Western Saharan participation, he added.

The agreement means that Libyan leader Muammar Qaddafi finally will be able to play host in Tripoli to the summit of the 50-nation African organization. The anti-American Arab leader will replace Moi, who has close ties to the United States, as the chairman of the OAU and will be able to speak as the leader of Africa for the next year.

The immediate victor, however, was Morocco, another friend of the United States, because it succeeded in preventing formal African recognition of Western Sahara, a barren, phosphate-rich, former Spanish colony about the size of Oregon on the northwest coast of Africa.

Morocco led a successful boycott of the OAU summit, originally scheduled for August in Tripoli, because of the presence of the Western Sahara delegation, which has been recognized by more than half of the organization's members as the legitimate government of the territory. Only 29 nations were represented in Tripoli, five short of a quorum.

The issue threatened to break up the OAU, dividing it along ideological and geographical lines. Polisario, which receives its weapons for the seven-year-old guerrilla war from the Soviet Union, is generally supported by leftist and pro-Soviet nations. Morocco's cause was generally supported by West African states and other countries friendly to the United States.

Ouko said Moi, as outgoing chairman, had suggested a target date of Nov. 23 for the meeting, to be preceded by a one-week meeting of African foreign ministers to set the agenda. The final date is up to Qaddafi, who is currently visiting North Korea.

A meeting next month would allow Qaddafi to address the United Nations General Assembly as the leader of Africa before the scheduled close of the assembly Dec. 18. Traditionally, the OAU chairman has combined the U.N. speech with an official visit to Washington, but it is highly unlikely that the Reagan administation, which has broken relations with Libya and has ordered Americans to leave the oil-rich North African country, would invite Qaddafi.

Qaddafi's chairmanship could strain U.S.-African relations, already coming under pressure because of the stalled U.S.-led negotiations for independence of Namibia, which is controlled by South Africa.

Some African countries accused the United States of working behind the scenes to sabotage the summit in August, but Ouko said he had no knowledge of such activities. He denied any such U.S. influence on Moi, who did not go to the failed summit, which was scheduled to start just days after an abortive coup attempt in Kenya.

Ouko said the combination of opposition to Western Saharan admission to the OAU and unhappiness over Qaddafi as the host brought about the boycott. He accused OAU Secretary General Edem Kodjo of acting "prematurely and unilaterally" in admitting Western Sahara in February on the basis of majority recognition rather than leaving the decision to the summit. Ever since then, OAU meetings have been plagued by the issue.

Ouko said he hoped the agreement reached in Dar es Salaam would "put back on the rails the prospect of solving the Saharan issue" on the basis of a cease-fire and a referendum to determine the wishes of the inhabitants. Kodjo's action, he said, had derailed that process.

In the interview, Ouko also criticized the slow progress in the Namibia talks and disagreed with the U.S. contention that a settlement must be accompanied by withdrawal of 15,000 to 20,000 Cuban troops from neighboring Angola.

"Kenya considers the two independent issues. They are non-related," he said, but he added that a Namibia settlement, which could end South Africa's frequent invasions of Angola, could "help us to convince the Angolans to get rid of the Cuban troops." Kenya is one of several African nations that "are not happy about Cuban troops in Angola," he added.

By linking Cuban withdrawal to independence for Namibia, "you're telling us you're not interested in solving the Namibian issue," the foreign minister said.

Most of his remarks, however, were favorable to the United States.

He said he was "greatly impressed" by new U.S. Secretary of State George P. Shultz and added that Chester Crocker, the assistant secretary of state for African affairs and the key American negotiator on Namibia, "is doing a good job."

Even his criticism was phrased positively. Asked to compare the Africa policy of former president Jimmy Carter with that of President Reagan, Ouko said, "We expect the United States to play a bigger role and speak more forcefully to South Africa on Namibia. I do not think the United States has fully utilized its capacity in dealing with African problems."

The foreign minister disclosed that he recently stopped in Johannesburg in transit to Swaziland. African officials generally shun white-ruled South Africa and normally would not even disclose a transit visit.

Ouko said South African officials took him to the VIP lounge at the airport. "This is the way we would like you to treat your own people," he said, a reference to Pretoria's discrimination against blacks.