Zimbabwe has been selected as the site of next year's summit of nonaligned nations, a move that the Nonaligned Movement hopes will focus continued antiapartheid pressure on neighboring South Africa.

The summit, scheduled for next September, will bring as many as 100 heads of state of Third World and developing countries "right to the doorstep of the hideous South African regime," Angolan Foreign Minister Afonso van Dunem said today.

Zimbabwe's selection as the summit site also means that it will replace India as chairman of the organization, a position that it will hold until 1989.

The decision on where to hold the summit began as one of the most contentious of the five-day meeting of nonaligned foreign ministers that ended here last night.

A number of delegations objected initially to Zimbabwe's selection primarily because Harare's principal backer was Cuba.

Havana hosted the 1979 summit, during which Cuban President Fidel Castro's attempts to push the movement into support of Soviet foreign policy backfired into bad feelings.

But condemnation of South Africa and a call for immediate mandatory sanctions drew overwhelming delegate support. That quickly turned into support for Zimbabwe as the only front line state offering itself as the next summit venue.

Cuba's attempts to lead the movement further to the left seemed to fall again into disrepute during this meeting.

A Cuban proposal for the members to declare a cancellation of payment of their hundreds of billions of dollars of debt, primarily to capitalist First World banks, disappeared with virtually no support.

In general, however, the 25-year-old Nonaligned Movement traditionally has found it easier to achieve consensus on those issues over which an outside power -- preferably in the West -- is selected for condemnation.

Thus, the ministers condemned U.S. interference in Nicaragua and unanimously approved a resolution calling for self-determination in the French Pacific territory of New Caledonia.

Proposed by the South Pacific island nation of Vanuatu, the resolution supported "an early transition to an independent New Caledonia in accordance with the rights and aspirations of the indigenous people," the native Kanaks who make up 45 percent of the population.

The resolution commended France and the Kanaks for "their stated desires for a speedy and peaceful solution" to disputes on the island, where more than 20 lives have been lost in the past year in fighting between the Kanaks and French settlers and police.

But its sponsor made clear that French failure quickly to grant independence would risk placing New Caledonia back on the agenda of the United Nations Decolonization Committee for the first time since 1957. The nonaligned members as a bloc hold a significant majority in the U.N. General Assembly.

"We would like to think that it would not be necessary," said Vanuatu's foreign minister, Sela Molisa. "But it will depend very much on the French," who have called for an independence referendum on the island by the end of 1987.

Meetings like the ones just ended here give officials from countries like Vanuatu a chance to mingle and exchange views with their Third World counterparts away from the watchful and pressuring eyes of the world's more powerful nations, and to receive a respectful hearing on regional issues that often get lost in other forums.

Although countries like France, Britain, China and the Soviet Union that maintain significant diplomatic presences here kept a hovering watch from the corridors, they were not allowed inside the meetings, where delegates approved position papers that will form the substance of next year's summit agenda. The United States does not have diplomatic relations with Angola.

The issues that caused the most discussion, however, will not for the most part appear on the agenda in any contentious form. They deal primarily with those battles that divide two or more nonaligned members. Although the movement prides itself on consensus, the level of universal agreement often is achieved by watering down or simply ignoring such subjects.

Although Iran and Iraq, both nonaligned members, reportedly engaged in a fearsome verbal battle inside closed meetings, the final conference declaration is expected to make reference only to movement hopes that they somehow stop their 5-year-old war.

Likewise, sentiment among former Portuguese colonies was strongly against Indonesia's ongoing occupation of Timor, but Jakarta persuaded the majority that such mention in the final declaration would be inadvisable.

To the extent that the movement took stands on divisive issues, it was at the expense of members Morocco and Argentina.

The delegates approved a resolution calling for direct talks between the Rabat government and the Polisario Front that claims to represent the people of Western Sahara. A similar discussion last year drove Morocco, which claims Western Sahara as its own, out of the Organization of African Unity.

Argentina found itself in the uncomfortable position of being the only nonaligned member to claim territory in Antarctica. Malaysia proposed a resolution that would declare the nonaligned believe that all of the Antarctic continent should be exempt from territorial claims and devoted to the welfare of international humanity, a proposal whose provenance was unclear but which seemed to delegates reasonably to fall within the cherished goal of "anti-imperialism."