The world's seven major industrial powers yesterday reaffirmed the agreement they reached at the Venice economic summit in June to defend the stability of the dollar and other major currencies "around current levels."

The finance ministers and central bankers of these countries said they "were pleased with the exchange rate stability which has been achieved and which has benefited their {countries'} policies and performance," and pledged additional action to enhance the process of international cooperation.

In a communique, they made special mention of President Reagan's decision yesterday to sign a budget bill mandating $23 billion more in budget cuts in 1988 as among "important favorable results" being generated by the process of economic cooperation that has evolved over the past two years.

The so-called "Group of Seven" countries includes the United States, Japan, West Germany, France, England, Canada and Italy. Their meeeting at the Treasury Department was preceded by a brief meeting of the Group of Five, which excludes Canada and Italy.

The communique said the seven nations "reaffirmed" that their currencies are within "ranges broadly consistent with underlying economic fundamentals. They recommitted themselves to continue to cooperate closely to foster stability of exchange rates around current levels."

But the generally confident tone of the major nations was brusquely rejected by spokesmen for the poor countries that call themselves the Group of 24. They warned yesterday that "the dismal outlook" for both economic growth and international trade may force increasing numbers of debtor countries "to limit or suspend debt payments."

Rejecting the G-7's assertion that exchange rates had been stable, the poor countries declared that "uncertainties" about exchange rates, as well as the recent pattern of higher interest rates, have meant a setback for the Third World. For the developing nations, the G-24 said, the 1980s are "fast becoming a 'lost decade.' "

The seven-paragraph communique issued by the seven richest democracies promised additional policy actions to keep their exchange rates stable. The ministers mentioned, in particular, efforts to to liberalize markets, pursue tax reform, adopt progrowth and anti-inflationary policies, and to reduce international imbalances.

"They {the ministers} reaffirmed their determination to fight protectionism, and promote an open world trading system," the communique said.

President Reagan's acceptance yesterday of the bipartisan fix of the Gramm-Rudman-Hollings deficit reduction act was taken as a positive sign that the United States is living up to its prior international pledge to whittle down the budget deficit.

Also noted, with approval, were the implementation of fiscal-stimulus programs in Japan and West Germany. But the communique also pointedly said that "it is important that {growth in domestic demand} improves further in some countries."

Reagan's move on the budget yesterday was expected to strengthen Treasury Secretary James A. Baker's ability to pressure West Germany to stimulate its weak economy, and to push Japan to take additional stimulative measures.

The president's action was the second step this week by the United States calculated to respond to international demands for specific actions to meet U.S. international obligations. The first was Baker's announcement last Wednesday that the United States would back a major increase in the World Bank's capital resources -- long sought by most of the 151 nations meeting here this week.

The U.S. actions are likely to increase the warmth of response to Reagan's address opening the joint annual meeting of the World Bank and International Monetary Fund on Tuesday morning, some foreign officials said.

A Reagan veto of the congressional proposal increasing the debt ceiling, but demanding a $23 billion reduction in the fiscal l988 deficit, would not have been considered "a positive sign", Dutch Finance Minister H.O. Ruding told reporters.

The G-7 communique was the prelude to, and sets the tone for, a series of international economic meetings that begin today the policy board of the International Monetary Fund, known as the Interim Commiteee, and conclude next week with the joint annual IMF/World Bank.

Sandwiched between the monetary sessions, a meeting of the joint IMF/Bank Development Committee will focus on the Third World debt issue, potentially the most explosive topic to be dealt with over the next several days. "That's where the action is," former Fed chairman Paul A. Volcker told reporters.

The sharp critique of the G-7 view by the poor nations in the IMF came in a communique issued yesterday by the Group of 24. It bitterly condemned the richer nations for limiting their help to the poor ones, and called for an "action program" of specific new stimulants.

The language of yesterday's G-7 communique closely followed and even duplicated language used by the Venice economic summit communique and by the finance leaders when they met at the Louvre Palace in February, notably on avoiding a further drop in the dollar.

Baker and new Federal Reserve Board chairman, Alan Greenspan, have taken the position that further sharp declines in the dollar could prove counterproductive to increasing growth in Japan and West Germany, and, besides, would threaten new inflation in the United States.

This cautious approach to the dollar was endorsed by most of the Europeans and the Japanese who have gathered here for the IMF/Bank sessions. They fear that any new dip in the dollar rate -- sending the yen and European currencies higher -- will price their goods out of the American market.

Ruding, who is also chairman of the IMF Interim Committee, told reporters that "it is not in the interest of the American economy itself if the rate of the dollar drops {further}." Ruding said that "many people feel that if the dollar goes down more, it will adversely affect" export-oriented countries in Europe.

Japan is fighting the impact of a yen already up 60 percent in the past two years. It has warned that any new instability might halt or reduce the flow of private Japanese investment funds, which have been helping finance the U.S. budget deficit.

Ruding predicted that at the long Interim Committee session starting this morning, "we can expect a lot of pressure on the United States to do more on its budget and trade deficits," and on Japan and West Germany to take stimulative action.

Administration officials made clear that Baker will keep up modest and private pressure on Japan and West Germany to expand their economies, and to keep their interest rates stable or lower. Recently, Japanese rates have turned sharply higher, and there has been a small increase in West Germany.

Privately, administration officials admitted this week that their bargaining position will depend on the deficit: if the government's red ink is coming down, the coordination process agreed to at the summit will be strengthened.

Although Baker, Greenspan and their counterparts in the other six major nations expressed moderate confidence in global economic prospects, the annual World Economic Outlook (WEO) of the IMF staff released yesterday projected a real growth rate of only 2.5 percent to 2 3/4 percent among the industrial powers in 1988. This is less than the 3 percent rate usually cited by the agency as necessary to keep the Third Worldeconomic situation from deteriorating further.

The report predicted that the American current account deficit -- goods and services -- would increase from $141 billion in 1986 to a record $152 billion this year, and remain at the high level of $141 billion in l988.

Meanwhile, the report estimated that the Japanese surplus would be edging down only marginally -- from $86 billion in 1986 to $85 billion this year and $83 billion in 1988. The other big surplus country, West Germany, would make only a moderately better adjustment -- from $37 billion in 1986 to $41 billion in 1987 to $33 billion in 1988.

But in a conversation yesterday with Washington Post editors, Japanese Finance Minister Kiichi Miyazawa said that the Japanese global surplus is coming down much faster than shown by the IMF numbers. Miyazawa said that the Japanese government predicts that the 1987 surplus will be only $77 billion. He had no figure for 1988.

Among issues likely to be debated in the Interim Commitee today, Ruding said there would be no final decision on IMF Managing Director Michel Camdessus' initiative to triple a $3 billion special fund for the African debtor nations. World Bank President Barber Conable, meanwhile, in remarks to African governors yesterday, said he was joining in the Camdessus initiative for Africa, and that he would also establish a new body -- the Council of African Advisers to the World Bank.

sw With respect to the different debt problems of the middle-income countries, mostly in Latin America, Ruding said that "there is a feeling" that banks should make more and new innovative instruments available to borrowers. American officials were promising a new Baker statement along such lines in his Wednesday speech to the joint annual session.

And on the much publicized exercise of developing a series of economic indicators to guide the IMF's surveillance of individual country performance, endorsed again by the G-7, officials said that there were unlikely to be major new developments at this time.

Staff Writer John Burgess contributed to this report.