New Union Shaky, Shevardnadze Says : Soviet upheaval: Commonwealth could bring economic turmoil, security breaches, political coup, he warns. But Yeltsin predicts an upturn in one year’s time.

Soviet Foreign Minister Eduard A. Shevardnadze said Saturday that he is not yet convinced that the commonwealth arising in place of the old Soviet Union can be “viable” and warned that the current turmoil in society could result in another coup.

Shevardnadze, a longtime ally of Soviet President Mikhail S. Gorbachev, raised serious economic, human rights and security questions in connection with the proclaimed Commonwealth of Independent States, now seen as the likely successor of the Soviet Union.

“The union, as it has existed for 70 years . . . does not have a future, but the commonwealth still has not shown whether it is viable,” Shevardnadze said in a speech to the founding congress of the Democratic Reform Movement, which he heads.

But Russian President Boris N. Yeltsin, who designed the commonwealth and proclaimed its existence a week ago in collaboration with the leaders of two other Slavic republics, predicted that the commonwealth will turn the collapsing economy around by the end of 1992. He also promised that there will be no hunger during this difficult transition year.

Shevardnadze, whose job as foreign minister includes international economic relations, said he expects an “economic depression” so extreme that the gross national product will decrease to half its 1990 level, that consumer purchasing power will fall 20% and that many factories will close, leaving millions unemployed.

“A lack of mechanisms for organized and coordinated economic reforms” will be to blame, he said, in an apparent criticism of what he sees as shortsightedness by the leaders of Russia, Ukraine and Belarus, the commonwealth’s three founding republics.

“They say there will be a unified currency system--and I’m not sure this will be a painless process,” Shevardnadze said in a conversation with reporters after his speech. “The division of debts is a very delicate problem. And the division of property, too.”

Shevardnadze forecast that political and security problems can be expected as the Soviet state is replaced by a loose association of many states.

“The central government is falling to pieces, and nothing is being created to replace it,” he said.

Shevardnadze said he does not have “full confidence” in what the quickly evolving situation will mean for world security, although he said that strategic nuclear arms are still under Gorbachev’s control.

“A completely new state structure is being created with new leaders,” Shevardnadze said. “What will the new setup be like? Who will possess the right to push the ill-fated button?”

Rapidly declining living standards combined with the collapse of state structures and the failure of new structures to take their place could bring violence, he said.

“The threat of a new coup--or whatever you may choose to call it, an uprising or a spontaneous riot--exists. I am greatly concerned,” Shevardnadze said. “I am not trying to scare anyone. I believe the threat exists. . . . Living standards are worsening by the day. . . . If we start calming people down by saying that nothing is going to happen, it will be irresponsible policy--simply irresponsible.”

Shevardnadze recalled that when he quit as foreign minister in December, 1990, warning of “approaching dictatorship,” many people scoffed at him.

“They said it was an outburst of emotions,” he said. “But it turned out otherwise. We must display vigilance now and do our best to prevent the worst.”

Shevardnadze urged the creators of the commonwealth not to make the same mistake that he, Gorbachev and other leaders of the perestroika reform movement had made by letting the transition phase last too long.

What is needed, he stressed, is the “rapid formation of some kind of coordinating center” to replace the Soviet governmental bureaucracy.

Gorbachev is prepared, Shevardnadze said, to help set up the structure, even though it is likely to make him obsolete.

“I think he can be very helpful in this process,” Shevardnadze said. “The Russian leadership as well as some other republic (leaders) understand this. My advice to him (Gorbachev) is not to make a hasty decision (to resign).”

Shevardnadze confirmed that he still holds his post as foreign minister and will meet Secretary of State James A. Baker III in that capacity today, although some Russian officials have called the Soviet Foreign Ministry defunct. He also indicated that his political prospects are good.

“Probably, in some measure, Shevardnadze may come in handy too,” he said in an obvious understatement. But he would not indicate what new role he might play, if any, in the commonwealth.

Carving up the Soviet Foreign Ministry--and foreign diplomatic service and the country’s embassies abroad--will be a “painful” process, he said. He also expressed concern that the new commonwealth would not abide by all of the Soviet Union’s international agreements, even though the commonwealth agreement states that member countries will do just that.

“Fifteen thousand agreements have been signed by the U.S.S.R. on a state level alone!” he exclaimed. “What about those agreements? Who will take responsibility for them? Not all the republics will want to.”

In other developments:

* The German heavy metal group Scorpions rocked the Kremlin with a private performance of its hit song “Wind of Change” after giving Gorbachev $62,500 in humanitarian aid. Gorbachev said the money would be used to buy equipment for children’s hospitals, the Interfax news agency reported.

* News reports from Kazakhstan said that the Parliament of that Central Asian republic is expected to declare independence Monday.

* Sales of rail tickets for trains bound for foreign destinations were halted because Soviet railroads owe their foreign counterparts $150 million, and the Soviet Railroad Ministry cannot pay. This development is another measure of the depth of the country’s economic disarray.

Russian President Yeltsin predicted in an interview with the Soviet newspaper Trud that the economic troubles will be under control by the end of 1992.

“At first things will worsen, then there will be stabilization, and in a year’s time things will start to improve slowly,” he said.

Even at the worst of times, he said, “the ‘food basket’ will be two-thirds full. There will be no starvation.”

Yet even Yeltsin’s vice president, Alexander V. Rutskoi, criticized Yeltsin’s economic policy, saying that there is a great “shortage of authority.”

“Will anybody manage this country after all?” he said in a speech at the Democratic Reform Movement conference.

Like Shevardnadze, Rutskoi warned that growing social tensions could prove explosive after state price controls are lifted Jan. 2. Prices are expected to rise quickly.

He said he doubts that economic stabilization will begin in the fall of 1992 as Yeltsin has predicted.