Against a backdrop of turbulence in financial markets and persistent huge trade imbalances, the World Bank and International Monetary Fund will meet here Sept. 29 through Oct. 1, with no sign that the major nations are ready -- or able -- to take any significant policy steps to improve their economic performance.

In separate annual reports, both the bank and IMF last week predicted continued sluggish growth in the year ahead, and pointedly called on the United States to trim its budget deficit, and on Japan and the European nations to take global leadership by expanding their economies.

Financial analysts have predicted that in the absence of such moves, the major powers will be unable to keep exchange rates stable, which could lead to another sharp decline of the dollar -- and possibly to a global downturn.

But the prospects for new measures to promote international cooperation appear minimal for the bank/IMF meeting, or at the policymaking sessions that precede it -- including the Group of Five major powers (the United States, Japan, West Germany, France and Britain); the Group of Seven (which adds Italy and Canada); and the IMF Interim Committee.

"Without saying that there won't be some additional agreements in respect to our policies, I think it's a mistake to expect such agreements every time there is an international economic gathering," a senior Reagan administration official said in an interview.

"Just because there's a G-7 {Group of Seven} meeting routinely around the fringes of the IMF and World Bank meetings, you shouldn't look for macroeconomic policy changes until circumstances call for them, and until the time is ripe to get them," he said.

The official said there is something of a policy stalemate now. Japan and West Germany are being urged by the United States to expand their economies, which would enable them to boost their imports from this country.

Japan and West Germany aren't prepared to make new commitments for domestic expansion, claiming that the burden falls on the United States to further reduce its budget deficit. Pending congressional action, the official said, the administration can't make additional promises on budget reduction or pressure its allies.

But the official added that the United States "will be in a very strong position to seek additional measures, if necessary, from our trading partners, if we are able to come up with a reasonable {budget} deficit reduction law or package for fiscal 1988, because of the great performance we've had in 1987."

Meanwhile, more than 3,000 official delegates, commercial bankers and other guests have begun arriving in anticipation of formal and informal discussions that will focus on the dollar and banking problems around the world; on the continued Third World debt problem; on Brazil's trial balloon -- quickly vetoed by Treasury Secretary James A. Baker III as a "nonstarter" -- for a unilateral writedown of its $110 billion debt, and on other proposals to relieve the debt servicing burden of the poorer nations.

The meetings also will mark the debut of Michel Camdessus, managing director of the IMF, who will make his first speech to an annual meeting, and of Federal Reserve Board Chairman Alan Greenspan, who will be attending his first sessions as deputy governor for the United States, whose delegation is led by Secretary Baker.

The delegates probably will talk among themselves about the lame-duck status of the Reagan administration, wondering, especially, whether the president will be able to ward off a new protectionist trade bill backed by a Democratic Congress. They also will be anxious to probe recurring rumors that Baker, the administration's highly respected lead policymaker on economic issues, may quit to help out in the George Bush presidential campaign.

Last week, Baker publicly denied that he was about to resign when it was brought up by C. Fred Bergsten, director of the Institute for International Economics, who was introducing Baker for a speech. Baker also has assumed management of trade policy matters since the death of Commerce Secretary Malcolm Baldrige in July.

Eventually, Baker -- who thoroughly enjoys his Treasury role, which makes him the most important Reagan adviser on a broad spectrum of key issues -- may leave the administration to help in the campaign of Vice President Bush, a close friend and mentor. But sources say that isn't likely to happen until after the end of the presidential primaries, or the spring of 1988, at the earliest. A leading possibility to succeed Baker, if and when he leaves, is Deputy Secretary of State John Whitehead, insiders say.

Another highlight of the 42nd annual meeting of the Bank and IMF is expected to be the address of World Bank President Barber Conable, who will seek to put to rest the charge that the bank's performance has been seriously damaged by a controversial reorganization that created staff morale problems. Conable plans to stress the need for renewed global economic growth and a big boost in the bank's capital.

Even though the general backdrop for the meetings is the weak economic performance during the past year, the senior administration official indicated that the United States will offer an upbeat economic assessment, rejecting "Armageddon projections" of a global collapse or depression.

He added that he and his counterparts in the other G-7 countries are "extremely pleased" with the progress already made in formulating a plan by which they attempt to assure that their economies, as measured by a few major indicators, are living up to promises and expectations.

In last week's speech to Bergsten's institute, Baker, who has been instrumental in devising the proposed system of indicators and the surveillance mechanism to go with it, said that the Group of Seven had developed "a process, a political mechanism" that provides a basis for economic policy coordination. He argued that through that process, the world has enjoyed stable exchange rates most of this year.

But some of the debate next week, especially in private conversations in the corridors and at cocktail parties, will focus on the question of whether the surveillance mechanism is strong enough to prevent a further substantial decline in the dollar -- or whether, in fact, a more appropriate policy might be to seek stability for the dollar at a much lower level in order to reduce the trade deficit.

Baker's position is that the worst is over for the U.S. trade deficit despite the record red ink of $16.5 billion in July. Rising prices, the United States contends, disguise the fact that the deficit in volume terms has already begun to shrink. Japanese figures confirm the trend, showing a decline in their trade surplus globally and with the United States.

Baker acknowledged in his speech that the surveillance system isn't yet fully effective. "We need a little more discipline in {it}. We don't get there overnight, and we are a heck of a lot better off today than we were a year and a half or two years ago, when -- I can promise you -- we didn't have meaningful meetings.

"We had a little 'tour de table,' everybody recited what their economies' prospects were, but there never was any serious discussion of efforts at coordination," he said last week.

Baker conceded that to make the indicators system more effective there must be "the political will" among the major nations to take the sometimes painful decisions that are necessary to achieve effective coordination of policy.

The Reagan administration claims success on the budget deficit front, citing a sharp reduction for this fiscal year. But independent analysts, including the Congressional Budget Office, predict a new surge of red ink in fiscal 1988.

Thus, officials of all countries privately agree that although they will go through the process next week of analyzing economic performance of the major countries against detailed forecasts prepared with the help of the IMF staff, the exercise will not produce an automatic commitment to act.

"While the indicators' exercise would pick up a shortfall in German economic growth," the Reagan administration official said, "we're not going to push them for additional measures until we can demonstrate a commitment to performance ourselves."

He pointed out that the United States is not normally in a position to give assurances on the budget deficit situation "until the beginning of the fiscal year, because we have a government of shared power, and we must work out through discussions and negotiations what our deficit plan is going to be." The new U.S. fiscal year begins Oct. 1, the last day of the meeting, and after the G-5 and G-7 meetings have taken place.

Privately, American officials concede that Japan's performance "hasn't been all that bad," and express hope "there will be no back-sliding." They are frustrated by West Germany's refusal, given the weakness in Germany's economic growth, to go beyond the tax cut already scheduled. But until the budget deficit picture clarifies here, Baker's ability to fire off broadsides at the German government is severely limited.

Meanwhile, Managing Director Camdessus, in charge of the IMF since January, has made clear that his agency takes the surveillance/indicators process seriously, and that it plans to play an increasingly important monitoring role. One source said that "what it comes down to is whether we can mobilize peer pressure in an intellectually more persuasive manner through the quality of our analysis, through focusing political attention on a few indicators."

In an attempt to put "flesh on the bones" on the indicators exercise, economists John Williamson and Marcus H. Miller argue, in a new study for the Institute for International Economics, that the Group of Seven nations' should establish a formula defining acceptable rates of growth for domestic demand, as well as targets for exchange rates. The authors said that reliance on a domestic demand indicator would show whether a country like Japan or Germany is depending too much on export growth.

On other issues expected to come up during the course of the sessions:

Conable will seek to put the reorganization morale problem behind him, stressing the bank's new commitments to exert leadership on the debt problem, and to give increasing attention to combating poverty. Conable predicts that his proposal for a substantial general capital increase for the bank, to enable it to hit about a $20 billion annual lending level in the 1990s from around $17 billion now, will get approval in fiscal 1988. But the United States will stick to the position that it will sign on for a capital increase "when the need for it is demonstrated."

Camdessus, at the IMF, intends to pursue the initiative he had launched earlier for tripling funds available for poor countries under the umbrella of the Structural Adjustment Facility. This was approved by the summit nations at Venice. But potential donors are arguing about "burden-sharing," looking to the United States to put up more money.

Japanese officials have promised to offer new initiatives to help solve the debt crisis among middle-income countries. In a mild criticism of the Baker Plan, Japanese Finance Minister Kiichi Miyazawa told the Financial Times that fresh approaches to the debt problem are needed, and that Japan has a responsibility to take a leadership role. Japan, which has already enlarged its participation in both the bank and the Fund, will be urged by others to do more.

Overall, the problems of the middle-income debtor countries will be aired at a meeting of the joint IMF/Bank Development Committee meeting Sept. 28. Coincidentally, a detailed report adopted last June by the Group of 24 (which represents Third World countries), recommending a broadened and more sophisticated role for the IMF in this area, will be discussed by the Interim Committee, but referred to the board for further study.

Despite growing and often angry demands from Third World countries for new forms of debt relief, the Interim and Development Committees will nonetheless both again endorse the Baker Plan's case-by-case solution to the debt problem. Baker is expected to offer only some modest refinements of the "menu" approach he unveiled last spring, designed to provide additional flexibility to the banks and debtors.

The perennial proposal for a new allocation of special drawing rights, the IMF's paper but convertible currency, will be brought up by the poor countries, but again will be pigeonholed by the Interim Committee.