PHUTHADITJHABA, South Africa (AP) _ The leader of South Africa's smallest and poorest black homeland today told President P.W. Botha that dividing the nation into tribal states will not solve the political problems of apartheid.

Kenneth Mopeli, chief minister of Qwaqwa, spoke after Botha dedicated a new government building on a hill overlooking the capital of this 240-square-mile homeland in the dusty foothills of the Drakensburg mountains.

Qwaqwa is one of 10 tribal homelands covering 13 percent of the nation. Four are recognized as independent republics by the South African government, and six, including Qwaqwa, are classified as ''self-governing states.''

Botha told 80 black legislators that ''the self-governing areas have a proud history'' and that development in Qwaqwa had convinced him the homeland wanted to be more self-sufficient.

''Those self-governing states desiring independence will be encouraged and assisted toward achieving it,'' Botha said. ''However, those areas that do not wish to take this step will remain an inextricable part of South Africa.''

He said homeland leaders such as Mopeli, who have rejected independence, will be invited to ''share in discussions on continued constitutional reform for all the black communities.''

Mopeli thanked Botha for the government's funding of the legislative building and described the president as one of South Africa's best leaders, but he challenged Botha's view of the future of the homelands.

''The self-governing states as they exist today are apartheid'' structures, he said, referring to the government's policy of racial segregation in which the 26.5 million blacks have no voice in national affairs. The 5 million whites control the economy and government.

''We are still convinced that our political salvation does not lie in the partitioning and fragmenting of the country into various parts,'' Mopeli said. ''We need ... a more viable formula. We would rather see the homelands develop as regional governments within a greater federal South Africa.''

Botha at one point mentioned the proposed National Council, an advisory body intended to negotiate a political system that would for the first time bring blacks into national politics.

Some council members would be chosen by Botha and others would be elected. Most prominent black leaders, including Mopeli, have rejected the proposal.

''No black leader wants to be seen promoting apartheid in any form,'' he said.