Prime Minister Robert Mugabe plans sweeping changes to put blacks in control of an independent Zimbabwe once he takes office next month.

Aides make it clear that despite his conciliatory gestures toward the white-minority community, he has ambitious programs to Africanize the civil service, curtail white control of the military, settle peasants on state farms and overhaul the media.

"We would not be a new government if we did not bring about changes," Mugabe said at a press conference a week after his landslide victory in the country's election for black-majority rule earlier this month.

Mugabe's predecessor, Bishop Abel Muzorewa, quickly lost favor with blacks when he took office last June after winning elections that failed to gain international recognition. He was seen as the handmaiden of the 200,000 whites and unwilling or incapable of making meaningful advances for Africans.

One of the key areas where Muzorewa was hamstrung was in the white-dominated civil service. Aides for the Marxist-inclined Mugabe say he has no intention of making the same mistake.

Under Muzorewa, all ministries retained white permanent secretaries who, in many cases, drastically curtailed the entry and promotion of blacks.

At the beginning of the London negotiations that led to the Rhodesian settlement, the spokesman for Muzorewa's government was white until the embarrassment of the contrast with black spokesmen for the Patriotic Front of Mugabe and Joshua Nkomo became evident even to Muzorewa.

The new prime minister has created a separate Public Service Ministry under Richard Hove to restructure the civil service to recruit and promote blacks.

Another key change will involve a reduced role for Gen. Peter Walls, the overall commander of the military. Many whites were surprised and pleased that Mugabe kept Walls on and this was a major factor in reassuring the minority community.

Most analysts feel, however, that Mugabe will only retain Walls for six months or a year in the top position, although he may continue to be in charge of integrating the three military forces.

Even though Walls will continue to head the military, he will lose some of his power immediately since the combined operations (Comops) administrative infrastructure he headed will be disbanded. Just before Muzorewa took office, Comops was expanded to take in all security forces, including the police, as a device to keep the military out of the hands of an African Cabinet minister.

Now, the police will be moved to the Ministry of Home Affiars headed by Nkomo and some paramilitary forces will be under key Mugabe aide Eddison Zvobgo, the minister of local government.

Walls will lose control of a large administrative staff with the breakup of Comops and instead will work under Mugabe who will also serve as minister of defense. As prime minister, Mugabe will also head a department of state security, which will include intelligence matters.

To many, however, it is amazing that Mugabe kept Walls on at all since he personifies the force responsible for most of the more than 20,000 deaths in the war.

Just last fall at the London conference that led to the Rhodesia settlement, Mugabe's spokesman Zvobgo asked during debate over the touchy issue of pensions for whites: "Can you imagine the ridiculousness of us paying a pension to Gen. Walls?" It didn't occur to anyone that such a government would continue to employ Walls.

Retention of Walls "was necessary to arrest white backlash, particularly from South Africa," the source close to Mugabe said. "Walls is doing for us what we cannot do for ourselves," sending home South African troops in the Rhodesian military and disarming the auxilliary forces loyal to Muzorewa. t

In his press conference Thursday Mugabe said his primary emphasis will be to resettle thousands of people displaced by the war, adding that the government would "proceed with speed" to acquire land for such purposes. Land redistribution is one of Mugabe's key reforms, mention of which sends shivers down the spines of the white minority, which controls almost all of the best land.

The prime minister has frequently said, however, that he plans to begin by buying unused and underutilized land. He also is hoping for Western aid to help buy land from any of the 5,500 white farmers who choose to leave.

Land utilization will probably be one of the first fields where Mugabe's Marxist ideology will become apparent. Resettlement of Africans on the land, the source said, will come in three different forms: individual, collective and state farms, but the emphasis will be on large state farms.

Mugabe also said a "major overhaul" is needed in the Ministry of Information and Tourism, to be headed by Princeton-educated Nathan Shamuyariri, since the ministry had been geared mainly to promoting the war effort and the country's unauthorized independence declared by former prime minister Ian Smith in 1965.

Mugabe has asked Britain to provide an advisory team from the British Broadcasting Corporation to recommend changes in the white-dominated Zimbabwe Rhodesian Broadcasting Corp., which controls television and radio. One change that has already come about is elimination of news broadcasters on local radio from Radio South Africa.

Education is another field bound to get priority treatment, with primary schools to become free next year. "Community schools," and idea borrowed from the American South of the 1960s to avoid large-scale black enrollment in white schools, will probably be eliminated.

A key problem facing the new minister of education, Dzingai Mutumbuka, will be returning to school upwards of half a million children deprived of education during the war. Thousands of facilities will have to be built or repaired.

Mugabe did not mention any major plans for the economy nor has he appointed a minister of economic development yet. Enos Nkala, the maverick finance minister who does not always speak for Mugabe, has talked about a vast redistribution of wealth but has not given any timetable. It remains to be seen how quickly Mugabe will move in this field, although he reportedly does plan to nationalize the country's nickel, copper, chrome and cobalt mines.