JOHANNESBURG, South Africa (AP) _ Jailed black leader Nelson Mandela on Thursday rejected reports that he has converted to capitalism, saying he is firmly committed to nationalization of banks, mines and monopoly industries.

Mandela, a leader of the outlawed African National Congress, has been jailed since 1962. He is expected to be freed within a few weeks and to play a role in promoting talks between the government and ANC.

The United Democratic Front, a nationwide anti-apartheid coalition aligned with the ANC, released a one-paragraph statement from Mandela that said he wanted to clarify his stance on economic policy.

''The nationalization of the mines, banks and monopoly industries is the policy of the ANC, and a change or modification of our views in this regard is inconceivable,'' the statement said. ''State control of certain sectors of the economy is unavoidable.''

Terror Lekota, chief spokesman for the Front, said the statement was issued because of ''innuendos in press reports that comrade Nelson Mandela no longer subscribes to nationalization and that in this regard he is in conflict with the external leadership'' of the ANC.

The statement appeared to be a response to a Jan. 14 article in the nationally circulated Sunday Times. It quoted wealthy black businessman Richard Mapanya as saying after a visit with Mandela: ''He did not believe in nationalization, saying it was clear that such a policy ran counter to the need to keep South Africa growing.''

The ANC's exiled leadership, based in Zambia, says it envisions a mixed economy for South Africa, but has an ideological preference for socialism. South Africa currently has a capitalist economy dominated by the country's 5 million whites.

An anti-apartheid Cape Town weekly newspaper, South, on Thursday published the text of lengthy statement it said Mandela wrote prior to his meeting in December with President F.W. de Klerk.

Justice Minister Kobie Coetsee said the government had no knowledge of any such statement. Some of Mandela's colleagues said the statement, even if authentic, might be many months old.

The ANC ''has no vested interest in violence,'' the statement said. ''But we consider the armed struggle a legitimate form of self-defence against a morally repugnant system of govenrment.''

The statement urged a negotiated settlement, saying ''an overwhelming majority of South Africans, black and white, hope to see the ANC and the government working closely together to law the foundations of a new era in our country.''

The key issue, according to the statement, would be how to reconcile blacks' desire for majority rule with whites' desire to avoid total domination by blacks.

Mandela, who is serving a life sentence for planning the start of the ANC's anti-government sabotage campaign, has been meeting regularly with government officials and anti-apartheid leaders. A group of five activists visited him Thursday at his quarters in a former staff home at Victor Verster Prison Farm outside Cape Town.

Business Day, the country's leading financial newspaper, said Thursday the government plans to partially lift the state of emergency and remove restrictions on the United Democratic Front.

The Front was effectively banned two years ago, but has been operating more or less openly since de Klerk assumed power in August.

The Business Day report cited unidentified government sources who spoke to the newspaper following Wednesday's meeting between de Klerk and his Cabinet.

De Klerk is expected to outline his plans for reform when he opens Parliament Feb. 2.

Business Day said de Klerk probably will announce a partial lifting of the 43-month-old state of emergency, which gives authorities widespread powers to crackdown on anti-apartheid groups.