Zambian President Kenneth Kaunda and Rhodesian Prime Minister Ian Smith held a secret, eight-hour meeting here in the Zaambian capital last Sunday, a Rhodesian government spokeman announced in Salisbury today.

The meeting, the latest dramatic developoment over Rhodesia, was reportedly devoted to a discussion of the current Anglo-American plan for a settlement of the 12-year-old dispute, and the possibility of a cease-fire in the black nationalist guerrilla war against the white minority government there.

The announcement in Salisbury astounded local Western and Zambian observers, who were totally unaware that the two foes had met here last weekened.

The Rhodesian government spokesman said the talks were held in a "cordial atmosphere" and included Rhodesian Foreign Minister Pieter Vander Byl and a top aide to Prime Minister Smith Jack Gaylard.

The Zambian government confirmed the meeting tonight but said it had achieved "nothing of great significance" and that Zamba attached "no importance" this approach by the Rhodesian prime minister. Only the armed struggle of the African nationalists in Rhodesia could bring about any results, the Zambian spokesman said.

The meeting was reported to have lasted from 9 am to 5 pm and to have taken place at State House, President Kaunda's official residence.

Informed sources here also said they understood the meeting had accomplished very little despite its length and that no concessions had been made to Smith on the issue of a cease-fire or the demand of the British and Americans that he "surrender" power peacefully to Britain, the former colonial power in Rhodesia.

The extraordinary secret meeting between Kaunda and Smith came amid mounting tension between Zambia and Rhodesia over recent incursions into this country by the white Rhodesian army in search of guerillas. On Aug. 31, Rhodesian jets attacked the border town of Feira with napalm bombs, killing three Zambian soldiers and wounding three others and two civilians.

Observers here were surprised that the Zambian leader had consented to meet with Smith in the current state of tension between the two countries.

President Kaunda has been pressing the British and Americans to make their peace plan workable by first forcing Smith out of power, suggesting that a total oil boycott be imposed on Rhodesia to achieve this. He said that the failure of the two Western powers to indicate how they planned to remove Smith constitutes a "glaringly false principle" of the anlo-American proposals.

In the wake of his increasingly tough public attitude toward Smith, it was not immediately clear why he agreed to meet the Rhodesian prime minister. Kaunda's preference for a peaceful solution to the Rhodesian dispute, if one is at all possible, is well known, however.