Prime Minister Robert Mugabe today named a white general, who led the former Rhodesian Army against the eventually victorious guerrilla forces, to be the supreme commander of Zimbabwe's military forces.

Mugabe's appiontment of his former enemy, Gen. Alexander Maclean, to Zimbabwe's highest military post showed once more that the prime minister is holding firm on his course of reconciliation between whites and blacks after a bloody seven-year guerrilla war.

Maclean's advancement above the commanders of the two former guerrilla groups that led the war effort also demonstrated that Mugabe has gained firm control over formerly unruly elements in the guerrilla forces that were unlikely to accept a white commander.

Lt. Gen. Rex Nhongo, former head of Mugabe's guerrillas, was named commander of the Army. His deputy will be Lt. Gen. Lookout Masuku, who headed the forces loyal to Joshua Nkomo, now a coalition partner in Mugabe's government.

A white civilian who has had a longtime association with the military said the appointment of Maclean was "immensely reassuring," a sentiment that is expected to be widely held among Zimbabwe's 200,000 whites. There are 7.4 million black Zimbabweans.

Typical of Mugabe's political style, however, Maclean's appointment was accompanied by a military reorganization designed to placate the black majority.

Black officers were given senior military command posts for the first time in the Army. Eight of the 10 white commanders and deputy commanders of the Army's five brigades were removed. They were replaced by black brigadiers and colonels drawn about equally from the ranks of Mugabe's and Nkomo's forces that have now been integrated into a national Army.

The replaced senior white officers are to be given new assignments within eight weeks.

Some white officers questioned just how much authority Maclean would have but said it was too early to tell. One said Maclean acknowledged to them that he was not consulted over the brigade command changes but told the officers to be patient.

The shake-up follows the introduction of another element into Zimbabwe's military picture -- the arrival of North Korean military advisers. A 150-member British military team is directing the training of the integrated Army and the North Koreans reportedly will train a special unit of about 1,000 of Mugabe's former guerrillas.

The minister of state overseeing military affairs, Emmerson Mnangagwa, declined comment on the North Koreans but said he would make an announcement on the subject in a few days.

Such training by the communist North Koreans could complicate the British military mission in the country and cause great concern among the remaining white officers. About half of the white members of the former Rhodesian Army have resigned since independence in April 1980.

When Mugabe was elected prime minister last year he named Lt. Gen. Peter Walls, former supreme commander of the Rhodesian forces, to head the newly independent country's military forces. At the time the move was regarded as essential to retain the confidence of the white minority and possibly to frestall a coup from within the ranks of the white-led military.

Mugabe fired Walls a year ago for criticism of the government and barred him from the country. The position was left vacant and few people expected to see it filled by another member of the military that fought to maintain white rule.

"I never thought this would happen," Maclean said today.

Maclean told reporters he was "stimulated by the challenge" and said he had no doubt that he would have good cooperation with the government. He said his biggest challenge was to set up a defense headquarters now that the command structure has been integrated.

Until now there has been a joint high command, with representatives of the former Army and the two guerrilla organizations and headed first by Walls and then by Mnangagwa, the minister of state in Mugabe's office.

Mnangagwa said the reorganization meant that the joint high command had been disbanded and that his role would cease, "except to see from a distance."

Under Mnangagwa's leadership, the government has disarmed guerrillas awaiting integration into the Army. The move greatly reduced security problems after two major clashes between Mugabe's and Nkomo's guerrillas killed at least 400 persons last November and February.

Mnangagwa said fewer than 10,000 guerrillas remain to be integrated. At that point Zimbabwe will have an Army of 65,000, about twice what is considered necessary. The government has talked about demobilizing about 30,000 soldiers, but Mnangagwa declined to give details.

A concern voiced by white officers was that Gen. Nhongo now will have command authority over them. In his early thirties, Nhongo is reputed to have had a drinking problem.

"He's a strange person," one white said, adding that the officers would take commands from him "as long as they are reasonable."

Maclean will chair a commander's committee to include Nhongo and the Air Force commander, Marshal Norman Walsh, a white.

Maclean, 49, entered the Army as a private more than 30 years ago and worked his way through the ranks. He served in the Commonwealth force, led by Walls, that defeated guerrillas in Malaya in the late 1950s.

When appointed by the previous government to the rank of lieutenant general and commander of the Army, he told a reporter, "All I ever wanted to be was a sergeant major."