International Monetary Fund economists predicted yesterday that the world economy will continue to improve through the remainder of the decade, with major industrial economies growing at an average rate of 3 percent a year and inflation continuing at a subdued pace.

Even so, in their "world economic outlook," the economists said that the growing U.S. budget deficit and persistent economic problems in Europe pose significant risks to their optimistic scenario.

So far, they said, the big U.S. budget deficit has had mainly beneficial effects on the world economy, by stimulating U.S. demand for foreign goods; but they noted that the deficit also has contributed to higher interest rates and has pulled into the United States savings that could be better used in other cash-short countries.

Unless the deficit is reduced, the IMF economists concluded, U.S. interest rates could rise sharply, choking off the U.S. recovery and injuring economies in the rest of the world. They said the deficit reduction measures advocated by the Reagan administration are the "minimum required" to make their optimistic scenario come true.

Unlike the United States and Japan, whose strong economies have helped fuel the world's recovery, European economies have been less able to shake off the recession of the early 1980s. The economists said Europe must deal with the resistance of old-line declining industries to the emergence of new, high-technology processes and must tackle a wage structure that is too high.

The economists said that the ability of the United States and Japan to adapt to changing circumstances -- fostering the development of high-tech industry and loosening the rigidities of wage rates -- goes a long way toward explaining their relative economic success in recent years.

But even as the economists deplored the large U.S. deficit -- with its potential for generating high interest rates, recession and eventually a return of inflation -- they said European countries may have to consider moving away from tight budget policies to stimulate demand.

But the economists said their best guess is that the United States will reduce its deficit, although not by as much as Reagan believes his proposals will, and that Europe will overcome some of its economic problems.

In that event, the world economy will recover, interest rates will fall modestly, inflation will remain far lower than in the early 1980s and the major debtor nations will see a continued improvement in their circumstances between now and 1990.

The IMF report was even more optimistic for 1985 and 1986. The world will experience balanced economic growth with the recovery spreading to developing countries during the next two years, the IMF report said. "For the first time in several years, the economies of each major region and group of countries are projected to grow at least as fast as their populations," the economists said. That should help moderate rising unemployment in such hard-pressed regions as Latin America.

The annual study by IMF economists was released during the spring meeting of the international agency's so-called Interim Committee.

Little is expected to be accomplished at the meeting. The United States and other major industrial countries, with the exception of France, continue to oppose calls from developing countries for new methods of dealing with the international system's financial problems. The developing countries want interest rate subsidies on their large foreign debts, a total reform of the international monetary system that would direct financial flows away from industrial countries and an increase in the IMF's reserve currency, the Special Drawing Right.

The so-called Special Drawing Rights are an IMF accounting device with a value that is tied to a basket of world currencies. Debtor nations, which have the right to get loans from the IMF that are valued in terms of Special Drawing Rights, believe that part of their problem is a shortage of liquidity -- or cash -- in the world and that an increase in these Special Drawing Rights would solve the problem.

Industrial countries disagree, saying that the debtor problems are not related to a shortage of world liquidity but rather to those nations' creditworthiness.

The major industrial countries, again with the exception of France, also believe that although some improvements can be made in the system of freely floating exchange rates that has prevailed for more than a decade, no major overhaul of the system is required.