Slowly but steadily, some of the whites who fled this country for South Africa after blacks took power under former guerrilla leader Robert Mugabe in 1980 are beginning to trickle back home.

Some are disillusioned by what they found in South Africa, sub-Saharan Africa's last bastion of white-minority rule, while others are attracted, albeit reluctantly, by the prospect of returning to a country that has done far better economically under a black government than they ever thought possible.

"A lot of people went down there feeling sorry for themselves, and a lot are now asking themselves why they left in the first place," said Clive Higgins, 25, a mechanical engineer who returned to Harare in August after four years in South Africa. "A lot of us made a hell of a mistake."

Their numbers are uncertain; many who did not notify the government when they left are equally unwilling to declare their return. But circumstantial evidence -- moving company manifests, long waiting lists at private schools, an acute housing shortage in Harare's wealthier suburbs and lines of white job applicants at some companies here -- all suggest the return of the whites is a genuine, if fragile, trend.

"Apparently the good news in Zimbabwe is a hell of a lot better than the bad news in South Africa," said Public Service Minister Chris Andersen, the sole white member of Mugabe's Cabinet. "I'm delighted to see them come back, because it's a vindication of what some of us said when they left. We told them not to run, that Zimbabwe would work -- and it has."

The white return in part reflects a dramatic economic turnaround in this region, which has always been dominated by South Africa. The white-ruled giant -- which has most of the railway lines, ports, power plants, minerals and the largest, best equipped army in the region -- still predominates, but some of the tables are turning.

South Africa once billed itself as the region's breadbasket, supplying food to many of its chronically hungry black neighbors. But beginning later this month, Zimbabwean grain trains will move south from Harare carrying at least 200,000 tons of white corn to South Africa.

The grain shipment is partly a fluke, resulting from a miscalculation by South African grain officials two years ago in committing for export large stocks of white corn, the country's main staple. But it also reflects the robust health of Zimbabwe's farming sector, which is projected in 1986 to produce a corn surplus of 1.5 million tons for the second straight year.

Similarly, while South Africa underwent its worst economic slump last year since the Great Depression, reflecting local and international unease over continuing racial strife there, Zimbabwe registered 5 percent real growth in its gross national product.

Fear of economic disaster following the 1980 electoral victory of Mugabe and his Marxist liberation movement was a major reason why many whites fled the former Rhodesia in the months following independence. While official statistics are unreliable, it is estimated that the white population fell from a height of 250,000 before independence to about 100,000 today, living among 8 million blacks. About two-thirds of the whites who left emigrated to neighboring South Africa.

But Marxist rhetoric aside, Mugabe's government generally has won points with western analysts for its steady management of the country's mixed economy. Meanwhile, many who left found the grass no greener in the south.

One problem was that the Zimbabweans headed south at a time when South Africa's decade-long economic boom began to falter.

"I never really felt comfortable down there," said engineer Higgins. "I was constantly under the impression from people I met that we really weren't wanted, that we were taking jobs away from their own people."

John Davies, 42, left Zimbabwe a few months after independence to work for a bronze foundry outside Johannesburg. When the bronze market collapsed a few months later, he went through a series of sales jobs and was laid off from his last job, working for a tractor-trailer manufacturer, a year ago because he lacked seniority.

Higgins was laid off from his last South African job, working for General Motors, at around the same time. Both men found jobs in Zimbabwe within weeks of their return.

Then there was the political situation in South Africa, which gave both Davies and Higgins a sense of deja vu. They said they saw South Africa heading slowly but inevitably toward a repetition of the white Rhodesians' long and futile struggle against black rule, which included a bloody, seven-year civil war and the loss of nearly 30,000 lives.

Higgins recalls seeing a magazine article about land-mine-proof civilian vehicles going on the market in South Africa and saying to himself, "Here we go again."

Davies said white South Africans ignored him when he argued that they would save themselves much grief if they accepted black majority rule. "They didn't want to believe it," he recalled. "But then we in Rhodesia didn't want to believe it, either."

The experiences of Davies and Higgins parallel the findings of a 1983 study of transplanted white "Rhodies" done at Rhodes University in South Africa. Author Alan Simon found that a majority of those in his sample felt they were not doing as well economically in South Africa as they had done in Rhodesia. Nearly two-thirds agreed with the statement that they would never be able to repeat the Rhodesian life style in South Africa, and most of them also said they saw South Africa inevitably facing the same problems that overcame Rhodesia.

Zimbabwe's government, pressed by a national unemployment rate as high as 25 percent and 80,000 new black job-seekers each year, views the white return with ambivalence. While officials look upon the trend as vindication of Mugabe's policy of racial reconciliation, they also fear that whites may take jobs away from qualified blacks.

"These whites are Zimbabweans," said Home Affairs Minister Enos Nkala, whose ministry oversees immigration. "If they have gone away under the wrong impression, and now they think they were wrong and want to come back, why not? It's a sign that there is stability here."

But government rules have been tightened in recent months. Whereas last year immigration clearances were being issued routinely, a committee of three now screens each prospective returnee, and applications are being processed at the rate of one a day. Officials speak of a waiting list at the Zimbabwe Trade Mission in Johannesburg of between 600 and 800 families.

Those who were born in Zimbabwe or who hold Zimbabwean passports can return automatically, officials say. But others must have jobs lined up and be able to prove their job skills are vaulable and in short supply.

"They are being screened very carefully," said Justin Nyoka, senior spokesman in the Information Ministry. "Some of our grass roots resent the return of these people. In the mining industry we heard specific complaints that people who left were returning as bosses. There's a feeling that if they come back, they should start again at the bottom."

Official immigration statistics indicate that more whites are still leaving than returning, although the gap has narrowed sizably. Net emigration -- the result of subtracting the number of those coming to Zimbabwe from the number leaving -- was about 1,600 for the first six months of 1985, down from nearly 6,000 during the previous period a year earlier.

But government spokesmen believe that the figures do not reflect the real trend, and there is evidence to support their view. Terry Bailey, operations director of a local moving company and chairman of the Zimbabwe Furniture Warehousemen and Removals Association, said his company is hauling goods from between 40 and 50 families back from South Africa each month, while shipping the belongings of 20 to 30 to South Africa. He said other companies in the association are showing similar net inflows.

The manager of a local abrasives company said that he has 80 job applications from aspiring white returnees on his desk. Most cannot get back in, he said, because the government believes the jobs they are applying for could be filled with competent local blacks.

Mugabe was stung by the unexpectedly large electoral triumph of his longtime foe, former prime minister Ian Smith, in last June's whites-only segment of the country's parliamentary elections. Since then, the government has devised certain tests of loyalty for whites, the latest of which was a 1985 law abolishing dual citizeship, which many whites here held. By the deadline last November, 19,424 whites in Harare alone had renounced foreign citizenship.

Many of the whites who have returned home display ambivalence about their stuation that is not dissimilar to that of the government. While most whites are glad to be back, they say they often feel less than welcome, are uneasy about the government's stated commitment to Marxism and uncertain about where they, and especially their children, will fit in the new Zimbabwe.

John Davies said he often stares of the map of the world on his office wall and muses about where he might go. "I can't just live from day to day -- I've got to think about where I'll be tomorrow," he said. "But where do you go? Any place you stick a pin on that map, there's trouble there, too."

Bruce Roberts, who returned to Harare from Johannesburg last year to manage a new chemical trading firm, said whites here are likely to end up like the Jews of Central Europe a century ago -- perpetual outsiders, welcome to engage in commerce or the professions but not in government.

"You get glimpses that the government appreciates that whites have a real contribution to make," said Roberts, a father of three. "I see myself staying. But the sad thing about Zimbabwe for whites is that a lot of our kids will grow up and leave -- and leave their parents behind."