Nine southern African nations agreed today to work toward closer integration of their economies in a major move to reduce their dependence on white-ruled South Africa.

At the conclusion of a one-day summit meeting, the nine underdeveloped nations, stretching from the Atlantic to the Indian Ocean and more than 1,500 miles northward from South Africa, approved a plan "to coordinate their economies to accelerate their development."

Although seeking to distance themselves from South Africa, the nine openly admitted that they are heavily dependent on Pretoria. They went out of their way to reassure their white-minority-ruled southern neighbor that no hostility was intended in the economic field.

"We want to clarify we are not declaring a war against South Africa," said Mozambique President Samora Machel, whose economy is closely linked to Pretoria.

The effect of the long-term plan is to acknowledge that black Africa must coexist economically with South Africa, at least for now, as the struggle for majority rule enters the final phase with white control having ended in Rhodesia.

Botswana President Seretse Khama, chairman of the meeting, stated the problem this way recently: "We have to deal with them, while condemning them for their evil policies.

Key elements in the plan adopted today include creating a joint transportation and communication commission, establishing a development fund to invite international aid and promoting cooperation in agriculture, industry and manpower training.

The declaration did not include any financial provisions, but called for a meeting of Cabinet ministers in September to work out costs, as well as an international donors' conference in November.

This first summit meeting in southern Africa to concentrate on economic matters was in effect an expansion of the five-nation front-line grouping of Zambia, Mozambique, Angola, Tanzania and Botswana that helped Rhodesia gain its independence. Rhodesia took part for the first time as did three nations closely tied to South Africa -- Malawi, Swaziland and Lesotho.

For a document involving the front-line, the joint declaration contained remarkably little of the traditional criticism of South Africa. There was only one reference to a "racist regime" and in at least two areas, anti-South African phrases were watered down from a draft declaration worked out by officials earlier.

It was apparent that the presence of the new members exerted a moderating influence on some of the more militant nations.

Although the atmosphere of the meeting was harmonious, there were reports that some friction had developed over efforts by Zambia and Malawi to soften the language even further. Tanzanian President Julius Nyerere and Mozambique's Machel blocked the move, informed sources said.

This is not the first effort at regional African economic cooperation but it is perhaps the most ambitious in the sense that the nine nations are attempting to move away from their major trading partner on the continent and change long-established commercial routes.

Excluding South Africa, less than 5 percent of trade on the continent is among African nations. Seven of the nine nations at the summit do more trade with South Africa than the rest of Africa combined.

South Africa has sought to take advantage of this dependence by trying to establish a "constellation of southern African states" in an effort to provide a buffer against hostile black African nations. In calling the economic meeting last month, Zambian President Kenneth Kaunda said it was partly designed to counter South Africa's plans.

"To link up our economies," he said today, "is important in the strategy for self-reliance against possible attempts by South Africa to undermine the independence of various countries in the region."

Aside from comprising a vast area with poor communications and transportation links, the nine nations face other problems that make them vulnerable to South Africa.

They have widely disparate economies, ranging from Marxist-oriented Angola and Mozambique to free enterprise economies with significant South African influence in Zimbabwe, Lesotho and Swaziland.

In addition, their products often compete with each other and the potential exists for jealousies, especially toward newly independent Rhodesia, which has the most developed economy in the region.

A recurring theme among the leaders was that southern Africa must use the newly won independence of Rhodesia as a springboard to advance not only political but also economic liberation.

"Political independence without economic independence is incomplete," said Rhodesia's new prime minister, Robert Mugabe.