A high-ranking Angolan official denounced the Reagan administration's support for visiting rebel leader Jonas Savimbi today, but he said Angola was willing to hold new talks with both the United States and South Africa to achieve regional peace.

Pedro de Castro Van-Dunem, a senior member of Angola's ruling Politburo, said Savimbi's visit to Washington would not change Angola's longstanding refusal to negotiate a political settlement with the rebel leader, whom it calls a tool of the South African government.

He said American support for Savimbi's rebel movement would only force Angola to seek more military aid from the Soviet Bloc, which already supplies billions of dollars worth of weaponry and approximately 30,000 Cuban troops and Soviet military advisers.

Van-Dunem's remarks followed an economic summit meeting here between the southern African region's nine black-ruled nations and foreign aid donors that closed today with a strong attack on U.S. support for Savimbi by the meeting's chairman, Botswana Vice President Peter Mmusi.

Mmusi, one of the black leaders in the region most closely aligned with the West, expressed "dismay and disbelief" that President Reagan had invited Savimbi to the White House. He said U.S. aid to the rebel leader, who also receives military and logistical support from white-ruled South Africa, would "run counter to American professions of friendship and cooperation" with the region's black states.

"This clearly places the United States in league with South Africa in fomenting instability in this region," said Mmusi.

The meeting, called by the Southern Africa Development Coordination Conference, was held to discuss projects that would help wean the region's small black states from their economic dependence on South Africa. The nine members contended that South African-supported rebel movements in their territories have cost them nearly $10 billion since 1980. Until Mmusi's statement, the conference had avoided comment on U.S. aid to Savimbi, which the region's black states strongly oppose.

Mmusi's statement angered the American delegates to the conference. The Americans were not given an opportunity to respond, but the delegation's leader, Mark Edelman, assistant Africa administrator of the Agency for International Development, said in an interview after the session that Mmusi's remarks were "gratuitous."

Edelman said it was wrong to suggest that "because the president of the United States decides to receive Jonas Savimbi on a private visit that in any way would reflect that we are quote, in bed, unquote, with the South Africans." The United States, he said, was still seeking to play the role of "honest broker" in the region and believed that there would be no peace in Angola until that government negotiates a political settlement with Savimbi's movement, the National Union for the Total Independence of Angola. It is usually known by its Portuguese initials, UNITA.

But Van-Dunem, who led the Angolan delegation here, said at a press conference his government would never hold talks or share power with Savimbi's movement, which he said was killing innocent civilians and crippling Angola's economy.

"We are open" to talk to Washington or Pretoria, he said, but "there can be no talks with people whose aim is purely to destroy the country."

Savimbi has waged a guerrilla war against the government ever since the Marxist Popular Movement for the Liberation of Angola took power in 1975 with Cuban military aid. Congress last year repealed a ban on aid to Savimbi, and the Reagan administration has submitted to congressional intelligence committees a plan to send $10 million to $15 million in covert aid to UNITA.

Noting that a U.S. diplomatic mission under Assistant Secretary of State for African Affairs Chester A. Crocker had visited Luanda three weeks ago, Van-Dunem said he could not understand how the United States could claim to support peace in Angola and at the same time aid the rebel movement.

Van-Dunem, who is also minister of energy and petroleum, said the conservative campaign in the United States to force American oil companies to pull out of Angola could have a serious impact on his country's economy if it succeeded. The Cabinda Gulf Co., a subsidiary of Chevron Corp., produces about 70 percent of Angola's oil in partnership with a state-run oil company. About 60 percent of the oil is sold to the United States.