WARSAW -- Despite Soviet leader Mikhail Gorbachev's repeated calls for "radical" improvement in economic cooperation, trade between the Soviet Union and its six East European allies is stagnating, and new technological and industrial projects are mired in bureaucratic entanglements, according to government officials and economists.

Since taking power two years ago, Gorbachev has appeared to make reform of economic relations the key element of his public policy toward Eastern Europe. While stressing Moscow's tolerance of the varied political styles of the region's leaders, he has forcefully demanded that cooperation within Comecon, the bloc's Council for Mutual Economic Assistance, be "raised to a new and qualitatively higher level."

Nevertheless, official economic reports and interviews with East Bloc officials indicate that Gorbachev's economic thrust has produced remarkably poor results. Not only are the new projects proposed by Gorbachev far behind schedule, but the overall contribution of Eastern Europe to the Soviet economy seems to have undergone a qualitative decline.

Gorbachev has made it clear that Moscow is counting on Eastern Europe to help the Soviet Union modernize its industrial base and narrow the West's technological lead. But according to official statistics, Soviet imports from the three most advanced East European economies -- East Germany, Czechoslovakia and Hungary -- actually decreased in 1986. Imports from East Germany, the bloc's technological leader, fell by 6.1 percent.

Meanwhile, these states dramatically increased their own imports of new machinery from the West, boosting spending by 30 percent or more despite Gorbachev's explicit warnings against such a step. Their example has been followed even by such countries as Poland, which, though already burdened with huge debts to the West, nearly doubled its imports of western machines in the first quarter of this year.

Only a huge Soviet increase in trade with economically backward Romania, the result of a major energy supply deal, and a smaller surge in trade with Poland kept overall Soviet-East European trade figures from showing an absolute decline in 1986. But even in Poland, a recent communique of the ruling Politburo conceded, progress in economic relations with Moscow was "far from satisfactory."

Polish officials concede that economic projects initiated under Gorbachev's leadership, such as joint Soviet-East European companies and direct trade links between East Bloc factories, have produced only marginal results at best, despite Soviet efforts to speed them up.

"From a practical perspective, actually doing something about {Gorbachev's goals} has been extremely difficult," said Adam Barszczewski, director of Comecon relations in the Polish Ministry of Foreign Trade. "So far, there are no visible results."

Western analysts say last year's poor economic showing may be partly due to exceptional factors such as the fluctuation in oil prices and trade disruptions caused by the Chernobyl nuclear accident. Gorbachev, they add, may be willing to tolerate poor results in Eastern Europe rather than risk conflict with its aging, entrenched leaders.

However, some western experts say the economic trends may aggravate tensions already incipient in Gorbachev's relations with his allies. "We cannot totally rule out that a major trade dispute is brewing between the Soviets . . . and East European countries," the Washington-based Planecon Institute recently reported. "Such a development would have major political implications."

At the root of the East Bloc's economic impasse is Gorbachev's effort to modernize a system of exchange dating from Stalinist times and inadequate for modern development. For four decades, trade among the members of Comecon has been conducted through rigid, annual government-to-government exchange agreements that preclude realistic prices, competition among the products of various countries or checks on quality.

Several East Bloc governments, led by Hungary and Poland, have scrapped this centralized approach in their domestic economies. They have demanded that Comecon similarly reorganize its trade, allowing for a free exchange of goods among socialist countries according to the market laws of supply and demand.

Gorbachev, although reportedly sympathetic to these views, has stopped short of publicly endorsing them. He has proposed what amounts to an interim reform, a series of measures that would allow Comecon governments to bypass the unwieldy annual exchange agreements without short-circuiting them.

The Soviet-backed measures begin with joint ventures, which would allow East Bloc firms to pool capital and technology for major industrial projects. Another Soviet innovation would create "direct links" between Soviet and East European firms, allowing them to trade goods, technology and expertise without having to go through government ministries or have their collaboration officially negotiated in a central annual plan.

Finally, Gorbachev has strongly pressed East European governments to participate in a "comprehensive program" for the development of new technology that aims through joint projects to narrow the technological gap between East and West. Comecon, Gorbachev argues, should work to develop its own new machines rather than simply buying or copying them from the West.

A chief impediment to this Soviet program, according to East European officials, is the continued split in the East Bloc between would-be reformers of the socialist economic system and conservative leaders who resist any departure from orthodoxy. Trade reform appears particularly threatening to poor countries like Romania, whose exports could be drastically reduced if other socialist countries were not effectively obliged to buy their products by the bilateral exchange system.

On a broader level, East European planners appear to lack confidence that any increase in economic ties with the Soviets could be good for their development. The rush of the dollar-poor Hungarians, Czechoslovaks and Poles to buy western industrial equipment last year showed clearly how little their countries are banking on Gorbachev's technological development drive to modernize their industries.

Attitudes, however, are not the only problem, officials say. Even in Poland, where communist leaders strongly back Gorbachev and economic planners support reform, the Soviet economic initiatives have bogged down, burdened with procedural and structural problems.

A Polish-Soviet agreement signed last October provided for five joint enterprises as a start and officials predicted that thousands of "direct links" would be established between firms in the two countries. But negotiations to set up the joint ventures have gotten stuck on such basic questions as how capital and profits will be divided and whether the firms will adopt Poland's system of workers' self-management.

Eight months after the agreement, Polish officials predict that none of the joint ventures will actually begin until early next year. Meanwhile, newly created direct links between Soviet and Polish enterprises currently account for only about 1 percent of the two countries' trade, according to Barszczewski of the Foreign Trade Ministry.

In addition to procedural and legal tangles, Barszczewski said, some of the new economic ventures have stalled on more fundamental grounds -- their lack of economic rationality. "We can't just do this in the name of political and ideological togetherness," he said. "This is the barrier: We have to figure out how to make these firms work on a sound economic basis."

Ultimately, many government and western economists argue, Gorbachev will have to push far more radical reforms on East Bloc economic relations to reinvigorate Comecon trade. The first step toward real change, they say, would be the creation of a free exchange system between the various socialist currencies as well as between these currencies and western "hard" currency. Currently, the money of the Soviet Union and its East European allies is nonconvertible, making a flexible and competitive exchange of goods among socialist countries impossible.

"In principle, no one is against these changes," said Barszczewski. "But changing things like this in a short time is very difficult. First of all, nothing is free; you need resources to carry out a reform. And changing the mentality of people who are accustomed to a very inefficient but very comfortable system is very difficult."