In the offices of Linquenda House here, bureaucrats of the Information Ministry almost daily turn out press releases vehemently denouncing South Africa, "the racist apartheid regime" across Zimbabwe's southern border.

On the roof, a few floors above their heads, sits one of downtown Harare's largest neon signs. It reads: "Fly SAA"--South African Airways.

This dichotomy between politics and commerce is reflected throughout the complicated and uneasy relationship between Africa's oldest and last remaining white-ruled state and its newest black-ruled one.

South Africa is considered Zimbabwe's number one public enemy, rightly or wrongly blamed for many of the country's economic and political woes and, simultaneously, its number one trading partner. While the front page of the semiofficial Harare Herald invariably reports the latest denunciation of Pretoria--one article this week called for an international military force to invade Namibia and wrest it from South African control--the business page dutifully records the peaks and valleys of the Johannesburg stock exchange.

A similar ambivalence can be found across the border. While South African blacks for the most part see Zimbabwe as a shining light of hope, many whites view it an example of what they want to avoid. "Remember Rhodesia" is the election rallying cry of white conservatives who argue that any change in South Africa's rigid racial separation codes could start it down the path to black rule like that which changed white-ruled Rhodesia into present day Zimbabwe.

South African newspapers regularly return the fire from their Zimbabwean counterparts. The Johannesburg Star said in a recent article that Zimbabwe might be preparing to legalize torture and compared its prime minister, Robert Mugabe, unfavorably with Stalin and former Ugandan dictator Idi Amin.

So far the war between the two countries has been one of words, not bullets. But that is subject to change. There are many officials in Harare who believe South Africa has embarked on a campaign to train and arm dissidents in southern Zimbabwe to undermine Mugabe's government. And there are strategists in Pretoria who, while they vehemently deny any role or interest in overthrowing Mugabe, believe the day could come when the two countries go to war.

"The truth is there are a lot of bloody fools in Pretoria and a lot of silly rhetoric here," said Anthony Upfill-Brown, a Harare financial consultant and part of the business establishment here working quietly to ease tensions between the two nations.

The leading rhetorician is Mugabe himself, who has a deep personal aversion to apartheid. "Abominable, barbarous, dastardly, cowardly" are just a few of the adjectives Mugabe has used in recent weeks to denounce Pretoria's actions. His minister of foreign affairs, Witness Mangwende, last week accused South Africa of "blatantly naked and unprovoked military aggression . . . and economic brute-bullying and blackmail" against its black neighbors.

But the translation of words to deeds is another matter. Unlike Mozambique and Angola, Zimbabwe has taken great pains to prevent the African National Congress, the main South African resistance movement, from establishing guerrilla bases on its soil. When Pretoria charged that four guerrilla operatives had infiltrated its territory from Zimbabwe this summer, Harare quickly dispatched a delegation of senior security officials to South Africa to review the evidence and restate its commitment to prevent such actions, according to South African officials.

Nonetheless, the South Africans have clearly lost patience with the flow of hostile words from the north, where Mugabe has quickly emerged as the leading antiapartheid spokesman of the black "front-line" states.

"We can live with a certain amount of rhetoric, but he goes beyond all bounds," said former general Hein Du Toit, who is now chairman of the national strategy department at Rand Afrikaans University in Johannesburg.

Relations between the two countries were strained even when both were white-ruled. South Africans still recall that British-born white voters in what was then Rhodesia rejected South African rule in a 1923 referendum largely because they feared subjugation under the Afrikaners of the south.

Pretoria was Rhodesia's closest ally during its years of white independence and struggles against black nationalist forces, but South Africa is also remembered here as the country that used its leverage to first force the Ian Smith government to the bargaining table with blacks.

That move eventually backfired on the South Africans, who had counted on victory for black moderate Abel Muzorewa in the 1980 independence elections. Instead, the winner was Mugabe, an avowed Marxist who had led one of the liberation groups, and the last man Pretoria had wanted to see in power.

Mugabe moved quickly to cut off diplomatic relations with South Africa, but allowed Pretoria to retain a trade mission here. The prime minister also made it clear he would "distinguish between political and diplomatic relations on one hand and economic or trade relations on the other." Zimbabwe, he said, was "prepared to continue cooperating on those areas where we believed economically we had to relate to South Africa."

Mugabe is said to have been privately relieved that Pretoria did not do more to undermine his new government early on. Still, South Africa has taken several opportunities to remind Harare that its economic dependence has a political price tag. Its early response to Mugabe's rhetorical assaults was to end a preferential trade agreement and withhold use of 25 locomotives crucial to the fragile Zimbabwean railway system. Both measures were withdrawn only after discreet intervention by U.S. diplomats.

The worst blow came last December when Mozambican rebels, who officials here believe receive supplies, training and guidance from South Africa, blew up the pipeline and storage tanks that supply Zimbabwe with most of its oil. For nearly two months, Zimbabwe hobbled along on emergency supplies while businesses lost millions of dollars.

"It made it quite clear that South Africa could mess up this place in a hurry if it really wanted to," said a western diplomat here.

Officials of South Africa's Department of Foreign Affairs disavow any desire to cause Mugabe problems.

"We are interested in stable government no matter who governs," said one diplomat. But Pretoria's military strategists are said to hold a more suspicious view and are believed to maintain an extensive espionage network within Zimbabwe to keep informed of security developments here.

The fact that most of the estimated 40,000 whites who have left Zimbabwe since independence have settled in South Africa has not made relations any easier. Though known derisively as the "when-we" tribe--because, it is said, every sentence they utter begins with "when we lived in Rhodesia"--the former Rhodesians have exerted a rightist influence on the already conservative South African government. An unknown number of former military officers from Rhodesia have joined the ranks of the South African Defense Force, and they are the ones whom Zimbabwean officials have accused of training and arming dissident bands against the Mugabe government.

Mugabe has done his best to trim his country's heavy reliance on its giant southern neighbor. South Africa's share of Zimbabwe's total trade dropped from 25 percent in 1981 to 20 percent last year, and Zimbabwe has taken the lead in promoting regional cooperation projects among black-ruled states.

Nonetheless, South Africa remains Zimbabwe's largest trading partner by a wide margin, and more than 85 percent of Zimbabwe's overseas exports move through South Africa's railroads and port systems. It is estimated that South African companies own at least one-third of Zimbabwe's capital stock.

While Mugabe continues to slam the South Africans, other Zimbabwean officials woo them. Businessmen from the south reportedly have little trouble meeting senior officials at the trade and finance ministries to discuss investments.

Zimbabwe's director of tourism, Etherton Mpisaunga attempted to drum up tourism to Zimbabwe in a visit to Johannesburg earlier this year, saying, "If South Africans have felt in the past that they are unwelcome in Zimbabwe, I want to dispel their fears."

Despite those soothing words, many foreign policy analysts believe both countries will be hard-pressed to keep relations from deteriorating further.

"South Africans generally think, 'Poor Zimbabwe, it's a pity it's going down the drain,' " said P.W. Esterhuysen, assistant director of the Africa Institute in Pretoria. "But the point is, we must beware we don't make this prophecy self-fulfilling."