ABUJA, Nigeria (AP) _ African leaders have voted at a summit to maintian economic sanctions against South Africa, but a splinter group defied consensus by announcing that its members will now openly trade with Pretoria.

For the first time in the 27-year history of the Organization of African Unity, its members were openly divided over the sanctions question.

Kenya, Madagascar and other nations say they will restore trade and transport ties as a signal of support for President F.W. de Klerk's political reforms.

Most of the organization's 51 member states voted Wednesday to keep up the pressure of sanctions to ensure that de Klerk keeps promises to abolish all racist legislation and move toward democracy.

As the organization's leaders met in Abuja, the parliament of South Africa took another step in that direction by abolishing apartheid laws that segregated neighborhoods for more than 40 years.

Despite the OAU's tough public stance, black Africa's legal and illegal trade with South Africa is increasing and is expected to reach about $4 billion this year, according to an OAU report published this week.

On Wednesday, the last day of an annual three-day summit, leaders said they were united about the need for democratic and economic reform on the continent, which is dominated by dictators and unwieldly centralized economies.

Nigerian President Gen. Ibrahim Babangida, newly elected chairman of the pan-African club, set the tone when he noted the organization's original goal of decolonization was achieved when Namibia became independent last year.

''The task before us now is to speed up our onward march toward unity and solidarity of our continent and the welfare of our people,'' he declared, to applause.

The issue of South Africa, regarded as an independent state, had hogged the spotlight at previous African summits.

Leaders focused this year on the continent's $270 billion debt, which is greater than its economic output; the need for economic integration and structural adjustment programs; and fears that a unified Europe will jeopardize Africa's economy.

The summit opened with 32 heads of state signing a treaty to establish an African Economic Community on the lines of the 12-nation European Community. Outgoing chairman Yoweri Museveni of Uganda lamented that while the rest of the world was pooling resources to seize the maximum advantage from growth, ''in Africa, we are busy taking action capable of leading to ethnic divisions, wars and secession.''

As the leaders met, conflicts continued to rage or simmer in Angola, Ethiopia, Liberia, Mozambique, Rwanda, Somalia, South Africa, Sudan and the Western Sahara.

Babangida promised that the priority of his yearlong chairmanship will be economic development and integration of sharply diverse economic and social patterns on the continent, ranging from Marxist dictatorships to constitutional monarchies.

Observers say it is a Herculean task. Africa's total trade is less than that of Belgium, and just 2 percent of that trade flows between member states.

Most African trade is firmly rooted with former European colonial powers, all members of the European Community.

Africans disenchanted with mismanagement and corruption began demonstrating and rioting to demand democracy 18 months ago. A handful of governments have fallen since then, and others have been forced to agree to institute democracy.

''Without democracy there is no way you can fight corruption,'' said Museveni, a rebel leader who took power in 1986.

Political party activity is banned by his government, which in January gave itself another five-year term of office, saying it needed the time to draw up a draft constitution.