Interest rates: topic 'A' for world economic summit

''There is,'' says C. Fred Bergsten, ''a steady erosion of world economic stability that could, given some flashpoint, turn into a real crisis.''

Thus Mr. Bergsten, formerly a high US Treasury official and now director of the Institute for International Economics here, defines the short-term outlook facing the United States and other industrial powers.

Lawrence B. Krause, senior fellow of the Brookings Institution, zeroes in on one of the major problems:

''The fragility of the world's economic system,'' he says, ''lies in the debilitating effects of high interest rates, country by country.''

High interest rates force cash-short companies and debt-ridden nations to spend more and more money trying to pay back loans - money that otherwise might productively be spent on creating jobs, goods, and services.

The result is a decline of economic growth, throwing millions of people out of work and plunging the industrial world into what may turn out to be the worst recession since World War II.

Business bankruptcies are running at a high level. Other firms stave off bankruptcy, but divert more cash to paying off debt. Investment for the future dries up.

Industries like housing and autos in the US are cash-starved and in a poor position to lead the nation into recovery when the recession ends.

Some nations, unable to pay for imports through sale of their own goods abroad, borrow more, until much of their foreign exchange is absorbed by debt.

Some banks find themselves dangerously exposed - that is, with too much of their depositors' money lent out to poor risks.

So far, bank failures have been few and, among major commercial firms, not many household names have gone down the drain. But the risk grows, so long as interest rates stay high, sapping the liquidity of corporations.

''What sort of damage are we incurring along the way,'' asks Mr. Krause, ''both to individual companies and to industries as a whole? That is the real issue.''

Most analysts agree that the stubborn refusal of interest rates to come down lies at the heart of the problem. But no one has found a way to bring them down without reigniting inflation.

In the US, President Reagan struggles -- so far vainly -- to convince the investment community and Congress that his policies will do the trick.

Stalemate ensues, typified by the current budget battle between Congress and the White House. European leaders, meanwhile, blame the US for their own plight, claiming that high American interest rates wreak havoc overseas.

Is the complaint justified? ''Twenty-five percent'' justified, says Krause. ''US interest rates exacerbate the problem for Europe,'' says Bergsten.

To minimize a flight of capital out of Europe into dollar investments, European central banks keep their interest rates competitively high. This stifles investment and borrowing by European firms, just as American companies back away from tight money policies pursued by the Federal Reserve Board in the US.

Both Bergsten and Krause cite indigenous problems, quite apart from the US, that contribute to Europe's economic woes. Prominent among these is a failure to restructure obsolescent industries, such as steel, to meet the rapidly changing conditions of world competition.

A major concern to Europeans is a huge influx of young people -- Europe's version of the postwar baby boom -- into labor markets that can't produce enough jobs. Forty percent of the 11 million unemployed people in the European Economic Community (EEC), officials say, are less than 25 years old.

These conditions add up to the ''steady erosion'' of the world economic situation of which Mr. Bergsten spoke. What kind of flashpoint might turn erosion into crisis?

* Default, or even inability to pay interest, by a nation deeply in debt to Western banks, says Bergsten, could contribute to a bank failure, threatening a loss of confidence in the international monetary system.

* Monetary instability, characterized chiefly by an overvalued dollar and an undervalued yen, adds to uncertainty. One result is an explosion of Japanese exports to the US.

* Protectionist pressures are growing -- what Bergsten calls ''a dangerous interaction,'' as governments succumb to the temptation to protect domestic industries by erecting barriers against imports.