While U.S. banks are taking an increasingly tough line toward South Africa and its debt problems, attitudes in Europe are less clear-cut but ultimately could prove more important.

There is every sign that the elusive governor of South Africa's central bank, Gerhard de Kock, knows this. Indeed, the reluctance of the Europeans to cut their ties could prove his strongest card in the debt crisis his country faces.

On the surface, the international banks that are owed $14 billion in short-term loans are unanimous: they all want to be repaid. But perceptions in the United States, Europe and Japan differ sharply as to how best to achieve this end and how to deal in the future with South Africa.

Until its unilateral four-month moratorium on repaying the principal of its international debts announced last Sunday, Pretoria was treated as a fully paid-up member of the western financial community.

The wide spectrum of opinion is rooted in commercial logic. Some banks in Britain and West Germany have heavy long-term exposure in South Africa, a reflection of strong, historical trading ties. Others, particularly in the United States and Japan, are essentially short-term lenders.

Above all, there is the political dimension, widely recognized as the cause of South Africa's financial crisis. In the United States, where the banks are more exposed to public opinion, banks are wary of any move that could be interpreted as bailing out South Africa and thereby propping up apartheid, the system of racial segregration.

But bankers in Britain and West Germany are taking a far more pragmatic view, in line with South Africa's deep indebtedness to them, but also reflecting how the banks in these countries are shielded from public opinion to a degree their American colleagues can only dream of.

De Kock is aware of these differing views and perceptions, as he showed when he surfaced, briefly, in New York for a news conference last Tuesday.

Blaming "two or three" American banks for triggering a crisis of confidence among international lenders for political motives, the governor said: "We will continue to repay all interest payments, and, if the American banks insist on withdrawing from South Africa, we will repay all money eventually -- not in three months, but eventually."

By contrast, de Kock sounded distinctly warm toward the European banks, which he said "have given no indication of not rolling over their credit to South Africa."

British banking links with South Africa are cemented through the presence of Barclays Bank and Standard Chartered Bank through their subsidiaries, Barclays National Bank (Barnat) and Stanbic. Earlier this year, both Barclays and Standard banks reduced majority holdings in their subsidiaries to just above 40 percent, a move that both stressed was unconnected to South Africa's political unrest.

Barclays, which has stated its opposition to South African racial policies regularly, intends to remain "constructively engaged," summed up by its claim that it is a "force for the good" in the country. Not all Britons agree, several Barclays branches having been daubed with antiapartheid slogans in recent weeks.

"We have been living with this for the last 15 years," said chief spokesman Geoffrey Kelly. "We recognize that we are a convenient target."

Commercial considerations weigh heavily, too. In 1984, Britain exported about $1.64 billion in goods to South Africa, the bulk in the machinery and transportation industries; imports amounted to $952 million, mainly key raw materials such as chrome, manganese and platinum.

This two-way flow of goods is critical for a trading nation such as Britain. Two thirds of British banks' lending to South Africa is trade-related; Britain accounts for $5.55 billion out of the overall South African debt of $18.5 billion at the end of 1984. About $2.65 billion of the $5.55 billion covers loans maturing within six months.

In West Germany, bankers are similarly vulnerable to South African demands to roll over loans because they already have committed at least $2 billion in financing.

The "Big Three" banks -- the Deutsche Bank, Dresdner Bank and Commerzbank -- are so deeply involved in short-term financing that they could not sever cooperative links without severe dislocation.

About $850 million of the $2 billion in outstanding loans supplied to South Africa by the West German banks will fall due in the next year, and some banking officials believe the figure could be higher.

In recent weeks, West German banks have been subject to protest from antiapartheid groups. Demonstrators brushed red paint on the pavement to depict "a trail of blood" between the Deutsche Bank and the South African Consulate in Frankfurt.

But money may talk louder. The German banks remain intimately linked in financing the activities of about 300 West German companies with branches in South Africa. West Germany exported $2.3 billion worth of goods to South Africa in 1984, chiefly machinery, electrical products and automobiles, and absorbed $1.2 billion in raw materials, according to Bonn's Economics Ministry.

A recent government report said that if chromium were reduced by 30 percent for one year, West Germany's gross national product would fall by 25 percent. Over two years, a chromium cutoff would cost 700,000 jobs.

In contrast with their West German counterparts, French bankers say they are likely to take a tougher attitude in financial dealings with South Africa.

According to a study commissioned by the World Council of Churches program to combat racism, France, with $1.09 billion in loans outstanding at the end of 1984, is fourth in the European lending league.

"Technically we are not particularly worried by this moratorium," said one French banker who spoke on the condition that he not be named, "but over the long term it is bound to encourage us to reconsider our exposure."

In Japan, banks have limited their loans to trade finance, usually extending to six months' maturity in the wake of "administrative guidance" issued by the Ministry of Finance some years ago.

During the past week, many Japanese banks have begun pulling back from trade finance, after the Ministry of International Trade and Industry (MITI) tightened its export-bill insurance program for South Africa, according to one banker and press reports.

Japanese banks buying bills sent by South African banks to Japanese exporters in payment for shipments could count on guaranteed payment by MITI if the bills were not honored by the South African banks. Now MITI reportedly is insisting on a case-by-case evaluation.

This has led many Japanese banks to refuse to buy South African bills, unless the exporter agrees to make good on them if South Africa does not pay, even though Pretoria has said the moratorium does not cover short-term trade credit.

This will complicate trade but not stop it. Exporters still can assume the credit risk themselves or insist on cash payment.

This, matched by several American banks' tough stance on short-term credit, is a disturbing trend for the South Africans. Trade is the engine that provides South Africa with its currently healthy balance-of-payments surplus, which in turn is the country's best chance of paying its debts.

Although there are obvious sharp differences on how much to lend and how soon to demand repayment, the international banks are united one one point: having unilaterally declared a debt moratorium, the South Africans are the ones who must come up with a solution; and that solution will have to contain political reform.