MOSCOW, DEC. 25 -- President Mikhail Gorbachev won approval today in the Soviet legislature to expand his authority and re-order the executive branch of the government to include a vice president and a new cabinet.

Under the constitutional amendments, Gorbachev will now preside directly over all top government bodies and will head both a Security Council, including the leaders of the army and the KGB secret police, and a Federation Council, comprising the elected leaders of the republics and autonomous territories.

Gorbachev has argued that the new powers and structures are necessary to assert order in the country. His opponents in the republics, including Boris Yeltsin, president of the Russian republic, have said Gorbachev is trying to establish a legal framework for a crackdown on the challenges to Moscow's authority in Moldavia, the Baltic states and republics in the southern region of Transcaucasia.

Although today's vote by the Congress of People's Deputies represents a victory for Gorbachev, he narrowly lost in an attempt to set up a new institution, the Supreme State Inspectorate, a presidential organ designed to ensure that all laws and decrees are obeyed in the republics. The legislatures of many Soviet republics have contradicted Gorbachev's decrees or refused to fulfill them, and almost all have declared the supremacy of their laws over those of the central government.

Although Gorbachev has sought and gained greater political authority in a formal sense, his popularity has plunged, and his ability to rule has been limited greatly by the conflict with the republics.

Gorbachev said he would return to the congress Thursday and attempt a compromise on the proposal for an inspectorate.

In the hallways outside the legislative chamber, Gorbachev insisted that he was not, despite warnings last week by Foreign Minister Eduard Shevardnadze, creating the foundations of a dictatorship.

"The people have demanded this from me," Gorbachev said, referring to the growing sense among many people that the destruction of the old systems of government and ideology have led to empty store shelves and a political atmosphere of complete chaos.

"Only in science is everything possible," he said. "In life, where processes come into conflict, we need to make choices."

KGB chief Alexander Kryuchkov also tried to reassure the public when he told reporters that the secret police plans "only to act within the framework of the law."

In an effort to take some of the edge off a scalding law-and-order speech last week, Kryuchkov said that, like Shevardnadze, "we in the KGB are also concerned about the situation in our country, and our task is to prevent any kind of dictatorship. Our task is to act under the law. But if the situation in the country goes haywire, the question of emergency measures may be raised."

"Even if the president is compelled to use extraordinary measures, this will not signal a return to the past," he said.

Yeltsin, who is by far the country's most popular politician, said he could not support Gorbachev's expansion of powers today and added that he expected that the republics would resist Moscow's attempts to bring them to heel.

"I am against all moves toward absolutist power," Yeltsin said. "Again we are seeing the old style of order and decrees, but they cannot take root in the soil of our new democracy. All the republics will resist."

Some radical deputies said they fear that a crackdown could begin in early January, probably in Moldavia, just as the world's attention will be focused on the increasing possibility of war in the Persian Gulf. Baltic deputies compared such a strategy to the Soviet seizure of their home region while the Nazis were marching into France, and others compared it to Moscow's invasion of Hungary in 1956 while the world largely was focused on the Suez crisis.

The congress also voted to eliminate the present advisory body, the Presidential Council, and with it the last remaining government post of Alexander Yakovlev, an academic widely known here and in the West as the architect of radical reform. He was especially active in the creation of the policy of glasnost, or openness in the press, politics and intellectual life.

Yakovlev, like Shevardnadze, has grown despondent in recent weeks with Gorbachev's rightward turn, according to sources close to him. Yakovlev and Shevardnadze, once Gorbachev's closest allies in the battle for radical reform, have become the chief targets for attacks by conservative critics in the military and the Communist Party apparatus.

"We were talking and I said, 'Alexander, what will become of us now?' " said a friend of Yakovlev's. "He said, joking of course, 'I am sure the bastards will shoot us in the same camp in Siberia.' "

The Council of Ministers also has been eliminated, and now all ministries will be responsible directly to the president.

Gorbachev hinted that he still was trying to convince Shevardnadze to take a post in his new government. Gorbachev said that until Shevardnadze's stunning resignation last week he had been hoping to make him vice president.

"Shevardnadze, I believe, is a man who has done a lot and will still do a lot," Gorbachev said. "The question of where and how is still under discussion."

Gorbachev has said the Federation Council would give the republics the ability to create and review all matters of domestic and foreign policy. Although some officials have said two-thirds of the cabinet would have to approve major decisions, Shakhnazarov said, "the last word is the president's."